If you use spacers, I don't think staggering makes much of a difference at all. It's an extra inch that is under the fender. Unless you spend hours looking at the back of your car, I bet you will bearly notice
As for performance, the stock 330 has 17x8 all the way around, but the sport package is staggered. When I drove both of them I didn't really notice much of a difference, and they have different suspension, wheel size, etc. So, I doubt you'll notice much by losing an inch off your back tires.
Hope this helps...