Case in point: Vorsteiner and its ludicrous GTRS4 wide body kit with the BMW M4. Part of the joy of the SEMA Show is that all of the best tuners in the world are competing to show off their wares ...

BMW claims 503 horsepower in M4 Competition tune, but dozens of easily googled dyno charts reveal the peak power is closer to 550 hp. The torque number seems to be accurate; BMW states the engine ...