back in the day, early to mid seventies, i ran a set of Dunstall mufflers on my 71 Bonneville, not only did that sound good, thay also improved performance a little,,, a friend of mine also had a set on his XS650 Yamaha, thay really improved the performance on that piece,, not sure if the Dunstalls are still avilable,,, also, just remembered, a mate had a set on his T150 Trident, now that thing sounded so sweet when it was up in the revs,,