I'd say it's the kind of thing you'd have to do a double take to cop it. But it would make for a really nice stance but keeping it oem.
Would only do it on a facelift E46 though.
I remember trying to do the maths, I think you'd get away with an arch roll and 225/40s instead of the 245s they normally have. E46 rears are 18x8.5 ET50 with 255/35