I think its about proportionality,a crew cab long bed could get away with larger dia. stacks than a reg. cab short box and IMO on any truck they need to be tucked as tight into the corner of the bed as possible and not stick up over the cab too much to look "right", also they need to be finished right, I've seen ones that are reg. exhaust pipe with clamped on tailpipe tips and they look like *****. Now if someone took a lil effort to weld/grind/ paint or plate that same setup it could have looked good. But to repeat a common theme here-do what makes you happy and what you like,dont worry bout others opinions. Those are words to live by, not just build a truck by!