Lately, I've been using Velocity series mufflers from Heartthrob. It seems like many mufflers, especially stainless ones, have what I call the 'Mer-cruiser' sound - at idle they sound like they're running underwater. I like mufflers that are nice and sharp at idle and under hard acceleration, but don't have the annoying drone on the highway. The Heartthrob Velocities fit the bill for me.