Hello, I have just joined if an attemp to get some additional information for a "decent" sounding exhaust system for my 2010 GT500. The car has 678rwhp and has just ruined the stock cats, which I knew it would. I now have a MRT off road H with the stock mufflers. Then sound is ok but the raspy, hissing, popping off the throttle is not good. Cats, resonators, No Cats, what is out there that will leave me with a decent muscel car sound?? Thanks