truedelta's reliability results are interesting:
http://truedelta.com/BMW-3-Series/reliability-13
It only breaks things down by engine for 2007 to 2009, but the results show that neither the 328i nor 335i are particularly low in frequency of repair. For 2007s, the 335i actually bettered the 328i, and the 2009 numbers are fairly close. 2008 doesn't look good for the 335i however.
Nor the M3 for that matter.