Redbob, your exhaust expertise is VERY informative and inpressive ! Maybe you can explain something thats been puzzling me. If you look at attached photo below, you will see a 3rd gen camaro muffler with a "h-pipe" connected between the muffler inlet and the r/s tailpipe. I got this off a website recently. Since I own a 3rd gen IROC with a stock muffler like the one shown, I'm wondering, will this improve performance/scavenging effect/sound good/lousy/etc. My car has no cats. Also since you were in on GM exhaust/muffler engineering, how restrictive is stock 3rd gen "cross-flow" muffler really. Aftermarket makes them seem like garbage. Your response would be much appreciated. Thankx.