I’ve had the pypes race pro transverse muffler on my 69z. These guys are right…idle its mellow and it will rumble on acceleration. There is no drone either. Here is a sound clip from when I had it on….
https://youtu.be/HlKiOeTDixg I now have Gardner on. I still have the muffler so if you can get a set of pipes I’d let it go for cost of shipping.