Pypes cat back

So my buddy with an 03 GT is looking to replace his stock exhaust. He was wondering how this system is.

Pypes THE BEAST Exhaust System (99-04 GT) at AmericanMuscle.com - Free Shipping!

I have the x pipe but I have no clue how these mufflers sound or the overall quality of their cat back systems. Does anyone have any experience with this cat back or the just the mufflers before I go and scour youtube for some sound clips?

Really? It looked like a chambered muffler from the pics I saw. Anyone else have any input? Thanks for the help.