Dynomax Super Turbos

I had Super Turbos on a 71 Challenger, 340, headers and 2 1/2 exhaust, turndowns before the rear axle. Not a chambered muffler sound like Flows. But a whole different sound on its own. I liked it. I would stay with the ST since they come with the kit. I am sure those guys at TTI know what their doing. But the Ultra Flows outflow the Super Turbos.