I had to scrap my stainless true dual system also, when I installed the new headers. It cost me $1000. That was for 2.5" stainless tubing, 2 free flow cats, 2 IMC stainless mufflers, hangers, labor. The IMC mufflers are just like a stainless version of a Flowmaster. They even sound like 'em. I should have just done a Hooker sidemount system in the first place like I wanted to. Oh well. Good luck with the Allen's system.