Why do you feel you "need" bigger tubes? Going all out drag racing with it? or just for the occasional street driver? reason I ask, is I see all this crap about "bigger is better" for exhaust systems, but it's been my experience that smaller works just as well many times and unless you can run different components back to back, and down the track, you probably couldn't tell the difference in many cases. Take the Shelby type tri-y headers I have on my 331 stroker motor in my 89 Ranger, from all I've heard they're a huge bottleneck to performance to a motor like mine, yet I couldn't be happier with the results, this thing makes power from 1500 to 6500 ( maybe more, but I don't feel the need to stretch things)