That muffler sounds pretty good to me, no gurgly noises like a Flowmaster (they sound like an out of tune Quadrajunk to me). I have 2" duals on my 235, all stainless, with a pair of CJ 7 mufflers and don't have any power problems. But I don't think that you would want want to run any larger than that on a 6 or even a mild v-8. Wild smallblock or big block maybe a larger pipe would be ok. If you want to make a big pipe look put a tip on the tailpipe the size you want.
By the way, a guy I work with who's int the import thing put a low restriction , no muffler, fart can exhaust on his '91 Accord, now he has a burnt valve on #3 and the engine has no power. Didn't have this problem until he did the exhaust.
