330i....Do it!! The sound alone will put a smile on your face!
Urban fuel consumption if driven nicely can be in the 10L/100km , open road it can easily drop into the mid to low 9L/100km. Some spirited driving will push it into the 12's to 13's.
The engine is bulletproof. So no worries about turbos failing etc. Also check the options on both.
I find the manual is a peach to drive, just matches the engine better....steptronic is nice too but offers a more relaxed driving experience.