[VTECaddict]

Huh? Pretty sure there has been a definite answer for a while.

The front calipers are direct bolt on, there's never been a question about that.

The problem lies in the rear. The 335i uses a larger parking brake so if you swap in the 335i rear brakes on a 328i, you will lose your parking brake. You will either have to modify the shoes by basically making a hybrid between the 328i and 335i parking brake shoes, or swap in the larger 335i parking brake mechanism, which requires changing to the 335i wheel carrier as well.

This is only a problem with RWD E90 325i/328i and RWD E92 328i. The 330i, E91, E93, and all AWD models all use the larger rear parking brake, so you can direct swap the 335i rear brakes on those cars and still have functional parking brakes without modification.