This is the setup I am using on my Cougar...
2.5" y-split, 2.5" high flow cat and Dynomax muffler, to a 2.5" to 2.25" split behind the gas tank and out 2.25" pipes and 3" tips.
It was all custom bent and welded for me. Professional work, done in 4 hours.
The sound is quiet at idle, and sounds like a loud V6 mustang at WOT. Doesn't drone on the highway more than one or two clicks of the volume.
My low end pretty much feels the same but the high end definitly pulls better. I don't have any dyno results though.
