Just slap 313 wheels on and your car looks the same as the iS from a distance. Honestly, I'd choose the 2011 335xi over the iS. The extra gas mileage is completely worth it, not to mention AWD that might save your life. The only possible thing you'll miss from the iS is the DCT. Otherwise, a $500 mod can overcome a car with 6k+ in difference. I'm sure BMS is working on a JB for the N55.
Plus, fully loaded = awsome. People will tell you that bare bone cars are purist for the driving experience. They're just either cheap or stuck with a used car/shitty options from the lot and are talking out of their ass to justify themselves.
Good luck and take care of your car!