I have a '99 V6, modded by a previous owner, etc. and frankly, you're best off with 18's. I don't know why kids my age are so obsessed by 20 and 22" wheels, it looks incredibly stupid and incredibly belligerent. Especially when you're running stock brakes/calipers which don't need the extra space because they're small enough as it is.
I think 18s are a good compromise, but unfortunately I'm running 18x9.5" in the front, so I may need a steering rack limitor, but we shall see. My suspension was lowered about an inch by the previous owner, which is why I am unsure.
edit: the opinions expressed here do not necessarily represent the opinions of the poster.