The Turbo Tuner attenuates the signal coming from the car's MAP sensor to make it think it is producing less boost than it actually is. All the other systems on the car are untouched, which means everything functions the same, just at a level that matches the requirements of the greater airflow. The car will still protect itself from overheating and detonation just like the factory configuration.
We almost couldn't believe the results with the Turbo Tuner installed. We've tested them in the past and have seen big numbers, but not quite this big. Apparently the intake and exhaust really start working well when flow rates go beyond what factory numbers require. For reference, the Turbo Tuner alone made 314 hp and 327 lb-ft at the wheels. The next step would be downpipes and a front-mount intercooler. Even with those two mods, the stock turbos start running out of capacity at the top end, meaning they will give mostly low-end power. Of the plug-and-play systems we've tested on the N54, the Turbo Tuner is the easiest and fastest to install. Your dealer may have issues with its use, so ease of removal is a good thing. We were assured that the Turbo Tuner doesn't force any system to work outside its designed range, so in theory it won't raise any red flags as far as your service department is concerned. But keep in mind we certainly aren't encouraging our readers to lie to their dealerships. We're just relaying information.