Thanks Smoltz for clearly that up for us. So you are basically saying in the States spec for spec the 335i is only 8.6% cheaper. That's not that much and when you factor in the more exclusiveness of the S5 over the 335i, it more unique body panels, seats, dials, etc. over the normal A5 (something that the 335i doesn't have) and I reckon it's worth the difference in price.
But then I knew that as I did already pick the S5 over the 335i. Good as the S5 is though it's no match for the M3.