Yeah, I have 18". Its not that big of a different compared to 17" comfort wise, depends mostly on what
lowering set you got. I had it lowered with Eibach springs and it was pretty decent. Depending on the weight of the wheel and how stretched your tires are you will lose some handling ofcourse but not that big of a deal on public roads imo. If you are going to do alot of trackdays, get a 17" lightweight wheel.
I actually just bought a
coilover set and installed it so its gonna go even
lower, but that will make it really rough. hehe, im bouncing around like mad on my 16" winter wheels atm. hehe