So far the best;

Chambered mufflers I have run are the Hooker Aero Chambers. *I think* there the best flowing chambered muffler.

Turbo mufflers are Dyno Max units. Quite & high flowing

Straight through mufflers would be ether the Hooker or Dyno Max / Max/Ultra flow.

These have been the best ones I have had in there design. And because each is a different design, they sound a bit different from each other.