Originally Posted by Jonjt
Agree with everything you said.
40hp is a significant. BUT!, it will take a good driver and proper instruments to actually see the difference 40hp brings, at least, if you are road racing. But, a 40hp increase will definitely make the car faster for most of the driving M3 drivers do. Lane changes, merging and illegal road racing will see a benefit with a 40hp increase.
Agreed. 40hp is signficant, but for every car that dynos a 40hp gain, there will be a car with the same mods that dynos only a 20hp gain and the owner will be scratching his head asking WTF?? My point is also in reference to the OP, who is considering a supercharger.