i just bought and installed a 3" stainlees pfs muffler. way to loud for me. i have a m2 down pipe, atr high flow cat, stock muffler ( took the pfs off ). when i put the pfs muffler on it changed the entire power band. almost eliminating the normal sequential turbo 1/2 kick. the engine also redlined very easily, is this normal? what about racingbeat cat back, is it quiet? other mods include m2 cold air box, stock computor remapped. 93 rx7