3.5" standard more like 2.5" i would say,as for boy racers tailgaiting you i have never had them doing it plus the wheelbarrow exhausts would be the only view of the car they would getI think they are 3.5inch standard, I wouldn't want to go any bigger than that to be honest and I don't think the twin pipes are the 182's finest point. Apart from looking abit wheelbarrow they make it look abit boy racer and you end up getting boy racers tailgating you and baiting you to floor it. Nice subtle flame red 172 with a stealth system for me.