S5 is a very competent car and good looking and all but so is 335i for a lot less money. S5 is a good car but not that good it justify its price over 335i. In Sweden 335i and A5 3.2q has similar price so if it was my wallet and my money my choice would be a 335i.
To be honest, I don't see 335i and S5 as true rivals. S5 is on its territory.
Only negative with 335i is the lack of a LSD (diff) IMO. That would certainly improve traction and handling. Luckily Hartge has a solution
