I don't see any reason at all. The 328 is a bit of a step up engine wise but the 335 is pretty much the same shit with a new body slapped on to it. The interior in the F30 is pretty nice but nothing to go WOW about and the body doesn't really stand out like the E90 did when it first came out. I rather wait and see how the F32 plays out by then I'll be ready to upgrade anyway.
Space Gray 2011 335xi E92
Old: Jet Black 2007 E90 (with xenons
and modded) 328i