avincent52's link of the M3 wagon pic proves they'd be dynamite. But that wagon has that full M3 look, which I think really makes those wheels look right.
The 325iT I just bought has the ZHP wheels, which look really nice, and are mildly staggered (8 & 8.5). I can't tell you if it makes much of a difference yet, as I don't have it yet! (But in a couple of hours I will!)
I'm partial to the CSL reps, though, and if I do a swap eventually, I'll go square, not staggered, for the exact reasons avincent52 mentions.