I've got a set of Doug's on my 340 hooked up to summit's 2.5" exhaust kit. Everything went together pretty easily. A few of the exhaust pipe sections had to be shortened so everything would line up, but that's all it was, cutting a few inches off a few of the pieces. Doesn't have anything to do with the Dougs either, the Summit exhaust is generic for A bodies, so it comes a little long, especially for a 108" wheelbase car like my Duster.