my idi has 2 1/4 straight pip to the rear and it's very loud to me. It cackels like no other at 2500 rpm. I've gotta be carefull in town cause there's a sound ordnance now and i shift at 1500rpm to be quiet. After i rebuild everything i'm gonna run a 3inch straight to the back right side with a slight turn down and a custom powercoated tip.