I drove the 328i and 335i quite a bit, including two back to back test drives. The engines, at least at the altitude I live at (6000 feet) are pretty close but the 335i does have slightly less turbo lag and a little more punch.
I drove both cars through the canyons west of Littleton and I thought the 328i handled a bit better it just felt a little more nimble.
You can't go wrong with either one, I picked the 328i and even with the extra weight of x-drive the car is a blast to drive hard.
** Removed - Tim330i **