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 G80 M3 and 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 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.