SKU: 1071534063

S58 JB4 Tuner for 2021+ BMW G80 M3, G82 G83 M4

$359.55 $399.50
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Description

S58 JB4 Tuner for 2021+ BMW G80 M3, G82 G83 M4Gains are 80whp 100wtq on pump gas and up to 150whp 175tq on higher octane or E85 mixtures. The ultimate tune for your S58 powered G87 M2, G80 M3, or G82 M4, the JB4 allows you to go from factory stock to full race and everywhere in between. The JB4 installs and removes easily and includes many unique features not found in any other tune, including user adjustable 1st and 2nd gear boost limiting, smartphone integration, electronic wastegate control,

Gains are 80whp/100wtq on pump gas and up to 150whp/175tq on higher octane or E85 mixtures.

The ultimate tune for your S58 powered G87 M2, G80 M3, or G82 M4, the JB4 allows you to go from factory stock to full race and everywhere in between. The JB4 installs and removes easily and includes many unique features not found in any other tune, including user-adjustable 1st and 2nd gear boost limiting, smartphone integration, electronic wastegate control, ethanol fuel support, and built-in advanced CANbus-based diagnostic tools. Installation is easy and completely removable with no splicing or cutting of factory wires making the JB4 an excellent choice for your S58 engine.

For the latest S58 performance results, updates, firmware, and map guide, be sure to visit https://www.jb4tech.com/forum/model-specific-engine-tuning-modification-discussion/m/27316-

Wirelessly connect the S58 JB4 to your Bluetooth 4.0 compatible iOS and Android® device via the JB4 Mobile connect kit or to your Windows® laptop with the BMS data cable. Both options allow you to record and analyze vehicle and tuning data, change JB4 performance maps, and update S58 JB4 firmware as we release free newer versions with updates, more powerful maps, and new features under development. A separate JB4 Mobile app purchase is also required. 

S58 JB4 FEATURES & BENEFITS

• Gains are 80whp/100wtq on pump gas and up to 150whp/175wtq on higher octane or E85 mixtures.
• Improves 0-60 times and 1/4 mile times
• Preloaded with custom S58 JB4 tuning software and up to 8 maps for various fuel and modification levels
• Ethanol (E85) compatible tuning maps
• Able to read/delete fault codes
• View and record up to 40 gauges/engine parameters in real-time with the JB4 app.
• Boost by gear in 1st, 2nd, and 3rd can be controlled via the JB4 app for a perfect launch
• Compatible with JB4 Mobile for smartphone logging, tuning changes, and adjustment
• The JB4 offers a lot more performance, functionality, and safety than your average performance chip
• Quick Plug & Play Installation
• CANbus OBDII integration offering unrivaled tuning features and performance
• Improved performance over non-integrated chip tunes
• Runs as smoothly as stock. This is how your vehicle should have come from the factory
• Compatible with all driving modes
• Fuel economy unchanged during normal driving
• 91 octane fuel or better required for performance gains
• Not VIN locked and can be removed without a trace and resold down the road
• Includes the rugged JB4 billet aluminum enclosure for protection
• Made in the USA
• Free USA Shipping
• 5 year warranty

 

S58 JB4 Vehicle Fitment

BMW M3
• 2021-Present S58 G80 BMW M3
• 2021-Present S58 G80 BMW M3 Competition

BMW M4
• 2021-Present S58 G82 BMW M4
• 2021-Present S58 G82 BMW M4 Competition
• 2023-Present S58 G82 BMW M4 CSL
• 2022-Present S58 G83 BMW M4 Convertible  

What is a JB4?

The JB4 is a plug & play tune available for turbocharged vehicles. The JB4 tuner installs between your car's sensors and its DME/ECU (computer) and manipulates vehicle performance through these connections making your vehicle much faster. While it's not the only tuning system that operates this way the JB4 separates itself from the competition with much more advanced connection points and processing, including CANbus, fuel & spark control, Bluetooth to your smartphone, and a variety of innovative and advanced features not possible with any other system. BMS regularly publishes free mapping and firmware updates adding performance and features as ongoing development allows. In addition, the JB4 system is not VIN-locked to your vehicle and can quickly be removed and swapped between cars or resold at a later time. Often imitated but never duplicated, the JB4 has been the gold standard in plug and play turbocharged performance tuning for over a decade.  If your looking for S58 tuning for your G87 M2, G80 M3, or G82 M4, the JB4 is a perfect S58 engine tune. 

Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 1071534063

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4.4 ★★★★★
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T
theman
Lake Worth, US
★★★★★ 4
Comfortable, easy to assemble, but no adjustable armrests
Color: Dark, Color: Dark
The Marsail Executive Office Chair Ergonomic Desk Chair with Flip-up Armrests PU Leather was an easy to assemble chair; I was done within 15 minutes with the included tool. Extra screws were included which was nice as the main pack had broken open and I couldn't find one of the primary screws in the larger box (my guess is I probably tossed it on accident with the packaging material) but had the backup so all was well. The instructions were well written and clear. I've now had the chair in my office for over a week. For context; I work from home and also am a PC gamer so I spend a sizeable portion of my time at my desk in the chair. I also live in the southeast US and its April when I am writing this review. With that said; its been in the 70s/80s regularly so feel like I can comment fairly on its performance in warmer temps; though I'll have to try and remember to comeback and update it for the summer season when AC is on full blast and humidity is higher (and the inevitable "swamp butt" sets in). In the first week I've found the chair to be comfortable to sit in. It is wide enough and the arm rests to the side enough that I can sort of lean left and right without much trouble. I like this wider seat and armrests compared to chairs with more narrow span as I tend to shift and move a lot while sitting. The PU leather material feels nice against my clothes and does "grip" the clothing which helps with my tendency to want to slide forward when sitting. At first I thought the "grip" would be annoying but I sort of like it after a week of using the chair. The cushion material is comfortable for sitting and rebounds well after I've been sitting in it for a long period of time. The armrests feature the same sort of cushion and PU leather material which makes them comfortable to sit back and lean on. For the price I think this is a solid office chair and a comfortable option. Longevity will only be tested over time so I'll see if I can remember to update this review over time. I am happy with the chair in my office. A few downsides about the chair that I have: - The wheels are very stiff and don't roll as smoothly as I'd like. They stay put when I am sitting at the desk but when I need to push away they take a bit of force. - The arm rests can't be adjusted for height. They are one height and can only be moved out of the way completely. For someone like who likes to lean or shift sides this is less than ideal as I'd normally make adjustments to the armrests. With that said it is nice to be able to move them out of the way completely when I don't need them. - Lumbar support could be better. I will be using additional support in the chair for my back.
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Reviewed in the United States on April 13, 2026
S
Sal
Boise, US
★★★★★ 5
Good for sitting on it daily. Not that soft as expected
Color: Dark, Color: Dark
I’ve been using this chair for a few days now and overall it’s pretty solid for a home office setup, especially for the price range. Assembly took me about 30–40 minutes alone and all the parts were labeled clearly. Nothing arrived damaged and the instructions were easy to follow, though attaching the backrest was a little awkward with one person. Once assembled, the chair looks clean and professional. The PU leather feels smooth and the cushioning is definitely thicker than cheaper office chairs I’ve tried. It’s comfortable for working several hours at a time, although I wouldn’t describe it as super plush or “sink-in” soft. The seat has a firmer feel, which may actually be better for posture during long work sessions. The ergonomic support is decent. The backrest follows the shape of your back fairly well and gives noticeable lumbar support compared to flat office chairs. I spend a lot of time at my desk and this chair helped reduce some lower back discomfort. The reclining and rocking feature is also nice for quick breaks between meetings or while watching videos. It doesn’t recline extremely far, but enough to relax a bit without feeling unstable. One feature I ended up liking more than expected was the flip-up armrests. They make it easy to slide the chair completely under the desk and also give more room if you like sitting cross-legged occasionally. The chair rolls smoothly and feels stable even when leaning back. A couple downsides though. The faux leather can get warm after extended sitting, especially in a warmer room. The mesh section helps airflow a little, but not enough to fully prevent heat buildup. Also, while the chair is comfortable, it doesn’t quite feel “premium executive” level in terms of materials. Some of the plastic components and armrests feel more mid-range than luxury. Overall, I’d say it’s a good value office chair with solid comfort, decent back support, and practical features. Great for everyday work or study use, just keep expectations realistic if you’re looking for a super high-end executive chair feel.
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Reviewed in the United States on May 6, 2026
R
Rose Petal
Draper, US
★★★★★ 5
Comfortable chair constructed with good quality materials
Color: Dark, Color: Dark
Having purchased several chairs from Amazon over the years, I would rank the Marsail Executive Office Chair Ergonomic Desk Chair as one of the better quality options I've received. Here is a breakdown of my experience: Build Quality & Aesthetics I was immediately impressed by the quality of the base. It is crafted from brushed metal and has a substantial, premium feel that sets it apart from cheaper plastic alternatives. Additionally, the pneumatic height adjuster was easy to install and operates very smoothly. Comfort & Ergonomics -- Padding: The padding is not quite as thick as I expected, but it has proven to be very comfortable to sit in so far. Sometimes I am in the chair as much as 10 hours per day, and the foam in the seat holds it's form all day. -- Support: The chair does not include built-in lumbar support, so I am using a lumbar pillow. However, I actually find this preferable; it allows me to adjust the pillow to my exact needs or remove it entirely depending on how I'm feeling. -- Head support and tilt: I like to work in an upright position, but I sometimes i like to lean back for a rest. The chair leans back just enough to allow me to rest my head, but not so much that I feel like it will tip over. The head support is subtle too - it doesn't hurt my neck or force me to rest in an awkward position. Functionality -- The mobility of this chair is excellent. The wheels are high-quality and roll very smoothly on my hardwood floors, which is often a pain point with other office furniture. Final Verdict Despite the thinner padding and lack of integrated lumbar support, the superior materials and smooth mechanics make this a decent value for the money. It’s a sturdy, well-made piece of furniture.
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Reviewed in the United States on April 12, 2026
B
Birdie, Las Vegas, Nv.
Lexington, US
★★★★★ 4
Good quality office chair with movable arms
Color: Dark, Color: Dark
This chair was relatively easy to put together. After unboxing and laying out all of the parts, my husband and I built it in 22 minutes. We noticed how the instructions have you put the tilt mechanism bracket on after putting the back and arms on. Another chair we built was the opposite, which made attaching it to the base actually easier. That way just made more sense. This way, you put the back and seat together using the arms, then you attach the tilt mechanism to the bottom of the seat, but the seat is at an angle when you do this. Then you lift the whole chair and place it down onto the legs. I'm glad there were two of us to do that part. We also noticed one of the holes for screwing in the arm bracket was not lined in metal like the rest of them were. It still worked, though. It does rock a bit back and forth. The height adjusting rod also locks the chair in place for when you don't want the chair to lean back. There is a knob underneath that allows you to loosen or tighten how much it moves when you lean back or rock. The material is faux leather. It looks like real leather and feels pretty good. This makes it easy to clean. The arms can be raised level with the back of the chair to make it easy to slide out of the side of the chair. Overall this chair has a pretty classic look to it and is comfortable to sit in. It even has some lumbar support. The way the back of the chair and the seat of the chair connect together leaves a little bit of a gap. Nothing major, but you could lose coins or keys through the gaps between the cushions. If you have a cat, this would be a great way for them to poke their paws through and say hello.
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Reviewed in the United States on May 20, 2026
B
Verified Purchase
Barshonk
Pawtucket, US
★★★★★ 5
Very good chair, comfortable and high quality.
Color: Black
I had my doubts, yet after a couple months I really love this chair. Its a very good quality. Comfortable and sturdy. It allows for me to lean back too, which is a big plus! It looks really great and I am glad I purchased this chair. If you are looking, then just buy it because it is as good as it looks in the pictures.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 4, 2026

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