Hi there,
I too, got the TTI system but upgraded to the Ultra Flow's. Big difference and much meaner sounding. I went on the website and listened to the two types to make that decision. I know it's not the best way to do it, but I'm happy.
Their on a 383 with Schumacher headers and 2 1/2 inch pipes. I was going to put a stereo in the car but I like the sound of the growl....
Good luck.
Tony