Summit exhaust systems, are they decent?

[ame="http://www.youtube.com/watch?v=AN9GmjZ7h3I"]YouTube- 1974 Duster with Summit Racing exhaust[/ame]

Audio clip of my Duster with Summit 2.5" exhaust with H-pipe, 5.9 Magnum engine and exhaust manifolds. Taken from about 6-8 feet behind the car, off to one side a bit with a Nikon Coolpix camera.