What is your favorite performance muffler?

Dynomax welded ultra flows. I was running the Summit turbos that came with the Summit 2 1/2" exhaust kit, but they started leaking at the crimped edges after about 700 miles. They sounded good, nice and mellow, until they started leaking. But they didn't hold up to the exhaust pressure that my 340 is putting out.

The Ultra Flows are significantly louder. It's a noticeable difference at idle, but at full song it's an entirely different ball game. The ultra flows are a lot less restrictive.