Stock muffler, hands down. So long as you can handle the slight amount of extra noise and it won't require hacking up your cowl to make it fit, it simply cannot be beat. It weighs 4.5 ounces compared to 10-12 for the bisson or slimlines, and the Bisson robs power, too. You could go CHP silent pipe or similar cannister, but you add an extra half pound, or a tuned pipe, which adds about a full pound.