It took a lot of playing and experimenting to get my exhaust sounding decent on my XR7. What I ended up with is true dual 2.5” pipes, high flow cats, a magnaflow dual in/out 18” x-pipe muffler mid-mounted, then a pair of thrush welded mufflers out back. This setup has minimal drone on the highway, and sounds good at WOT and idle. It does drone a bit around 60mph, but at 75+ it sounds pretty good. If you aren’t going for lots of power, doing 2.25” pipes instead would quiet the system down a lot. Definitely keep the cats though, as they help a lot with reducing drone.