I compromised and fitted a 3.5" down pipe you can get the 4" in you need a porta power and you have to push the little footrest in on the floor from underneath to get clearence takes a bit of work. Rocket sports truck in Victoria fits them also Beaudesert exhaust in Qld. Has their own system very good work. I had to pump my floor to get the 3.5" in also you can call me on 0429178204 if you have any questions