Not wanting to take anything away from TYGA, but if you want direct bolt on cans the ones made by Swarbrick are very good and fully rebuildable. As I recall when coupled with a wire splice they gave just over 1hp gain over the stock ones.
Maybe I'm sad, but I quite like the sound of stock cans, they are louder than you would exspect.
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If I have to take the carbs off once more...