OK, the Thorley headers are in. Billy used the stock Y-pipe minus the cats. That runs back to a single 3" pipe which runs into a single in/single out 3" Spin Tech muffler. The 3" pipe out of the muffler is dumped right before the rear axle.
The truck sounds AWESOME at idle. I love it. But when you get on it (anything much over 2k rpm) it's what I would call obnoxious. Pretty loud and not really a mellow tone.
So my question is: Is that a result of not having the cats in there? Would adding the cats mellow it out some?