The RS4, honestly is not that much faster than a stock 335i. From a 5mph roll, my RS4 just inches away from the 335i, not remotely close to "TOASTING" the 335i as someone suggested. Ran from 5mph to 100 or so and I was maybe 2 cars ahead but still inching away. It wasn't like my 997Turbo vs the 335i, the Bmw and RS are very similar in speeds. Like most have said, they are 2 different cars alltogether. Fun factor, not sure if you have a 335i Coupe, 6spd, etc, but I find the 335i to handle just as well as my RS4, not sure on a track though (but I never really cared too much about that figure as I drive on streets daily and not on tracks). In any case, good luck with your decision.