I have gutted pre-cats, a Black Dragon Automotive replacement cat, and the HKS cat back. I like the sound of it. Not too loud but you can hear it when I really get on it.

 

I have the RB header, Mazdatrix hi flow cat, and the RB ypipe setup. Not tooo loud but I try and soft pedal it in my neighborhood. nice sounding to me. Even the wife thinks it sounds cool, if she doesn't have to ride in it!



I plan to do a single 3" pipe back from the cat and one hi flow exhaust muffler that can be removed and replaced with a pipe on race days... we hope the cat will knock down enough noise to pass track db... Reduces weight and hopefully avoids the 1-3 hp a Y-pipe robs. We'll see how it does... Jeff Clark is going to work with me on this.

 

the old greddy and the old hks (now called the sport) sound great!

 

makes sense