Here's mine that I took off my W211 E500 before I sold the car. Not sure exactly how it works but there is definately a difference during half throttle or WOT. There is less of a lag when you give it gas and more responsive (especially on Automatics with TC) although it does not produce more HP. I'm hoping this will fit on the S5 once mine arrives next year. BTW....easy 5 minute bolt on.