There's very little differences between 09, 10, 11.
There's BIG difference between those and an 08, however.
Betwen 09, 10, 11, maybe LED tails, different oil caps, updated map (but same CIC I drive), updated idrive with bluetooth and ipod app and stuff (not familiar), position of heated seats, and the notorious start/stop in 11 models, and that's about it. Nothing major in mechanical, technical, or aesthetics.
I was in the same market as well, didn't look for an 11 because of
2. was still rare when i was searching in 2012
3. i hated the notorious start/stop technology and thought it was useless, and I didn't want ANY additional electronics that I didn't need...(plan to keep the car long)
4. don't need 11's competition package. All i need is 359 Comp wheels which i can get later and i know imma lower the car with KW V3 coilover later...
but more important would be the previous use of the car, more so than the MY.
1. "best" previous history
2. low mileage (but not TOO low...a properly used engine is better than never used sitting home garaged engine)
3. good option list + good price