I took your word for it. my friend and I installed mufflers last night - he got a thrush glasspack, and I got the Red Hots - and I am so incredibly happy.
we just cut the muffler off behind the cat converter, once we got the muffler and old cat back out (after raising the frame with a floorjack) we just went and hung the new mufflers right there.
but since we ordered the wrong size (2 inch, the piping after the cat is 2 inch - so be sure to buy the two inch slip fits, which they offer, cause we didn't) we had to go to autozone and get some piping to fit the mufflers up. we also got a turndown to push the gases at the ground. we welded the front adapter piece on both of them, and clamped the turndown on his thrush muffler - I took the time and welded both the seams on my muffler. then we clamped them to the stub left over behind the Cat.
and they are great. his has more of a truck sound, the "woaht" sound, and the redhots deliver more of a race car sound "wooht", while producing a low rumble at an idle.
one of our friends has a summit glasspack installed the same way (but he didn't weld the hangar back on - hehehe) and its funny how our three rigs - set up the same way, sound so different, the summit muffler gets a little ricey at high rpms, the thrush muffler gets a nice "truck" sound all the way through the powerband, and mine sounds more like a nascar race car.
and it was fun to see what the 4.0's sounded like without any muffler and just the Cat.
(sorry, 16 and 17 year olds just want to tickle the brain in that way.)
either way - I am incredibly happy with my muffler, my friend is happy with his thrush, and the other guy is planning on switching to a chambered muffler simply because he didn't do a good job installing his muffler (<--- lol)
have fun - because I will