What is your favorite performance muffler?

i love the sound of these on my demon mine has an X pipe so it sounds a bit smoother and a bit of a higher pitch than the clip.i'm guessing the gto in the clip has eather a H or no crossover.
[ame="http://www.youtube.com/watch?v=BoQdGQpwZk0"]71 GTO with Xlerator mufflers_0001.wmv - YouTube[/ame]