I have a 325i LCi with the same 3.0L engine as the 330i. (Just de-tuned)
I understand the 330i gets the same MPG, and I currently get 32mpg out of mine.
I drive with a fairly heavy foot, and do 60/40 Motorway and city.
Would recomend the engine, but it does need to be worked. None of that imidate pickup you get from a d when crusing. Drop a cog or 2 and you are flying and smiling ear to ear tho ! :d