RENNtech HHT (hand held tuner) allows you the unlimited ability to switch between tuned and stock ECU programming and requires no ECU removal! Proprietary tuning module stores both the RENNtech tuned file and your vehicles stock file. The module plugs directly into the OBD2 port and delivers the file you choose directly to the ECU. Programming takes only a few minutes and the vehicle can be re-flashed at any time as many times as you wish.

RENNtech M157 Biturbo ECU+ Upgrades are TÜV approved!

Our proprietary ECU+ upgrade for the Mercedes M157 Biturbo 4-MATIC engine offers huge gains in performance across the entire RPM range without sacrificing around town comfort or daily driver reliability.

Notes:

• We have found the M157 engine stock performance numbers vary from the baseline figures claimed by Mercedes Benz. We typically see higher baseline numbers than claimed by the factory.
• Power gains are calculated based on stock numbers measured by RENNtech. Crank Performance Numbers are calculated with a 17% Drivetrain loss on 4MATIC vehicles.
• Our numbers will be dependent on conditions and fuel quality. 93+ Octane gasoline is mandatory with this Performance Upgrade.
• States known for poor fuel quality have to be supplied with a lower power setup. Please call for details and Race fuel options +1-561-845-7888.