I would be really torn if I had to choose between the 335i and the S5. If I decided I didnt care about a warrenty and wanted pure speed then I think the 335 is the only way to go. But stock for stock I think the S5 is the sexier car. But its a tough call and would probably come down to a test drive for me. In the end the S5 would have to impress me enough to shell out 10k more than for the Bimmer.