Mufflers like Dynomax
For another option and lifetime warranty, Pypes makes their Race Pro which is the same design at the stainless Ultra-flow. They also make a Turbo-Pro which is the same design as the DM Super Turbo but Pypes is in a welded case and stainless. They also have a couple other mufflers but I think these match this topic best. It's worth a serious look.