This add on kit for BMW N54 engines allows your JB4 to "2step" the engine (cycle power to the coils) to build boost when not under load. Useful as both a noisemaker for both manual and automatic transmissions, and for launching with manuals transmissions. It also allows No Lift Shifting (NLS) for manual transmission cars.The relay kit requires a JB4, back end flash map, and BMS data cable or JB4 mobile connect kit. Note that we've modified the JB4 firmware recently so that the clutch wire is no longer required simplifying the installation. Update your JB4 firmware before or after installation to v32_15 for twin turbo or v13_7 for single turbo to enable. Less