Today we tuned a BMW 335I N54 to stage 2. The car had a full exhaust including turbo back exhaust and the cat removed. We had to disable the rear O2 sensors in the ECU file to prevent faults.
The car started off at 305 HP and rose to 390 HP after our ECU tune. Torque output factory was 400 NM and increased to 520 NM at the flywheel.
Find out what we can do for your BMW here https://www.alttune.com/vehicle-search/