I don't think you'll have to rejet, but you may end up tweeking your A/F screw a tad to richen it up a bit. Honda has your bike set up on the lean side from the factory. You'll just have to check your plugs afterward to see how it's burning. Others who have done it will chime in. The PO of my shadow opened up the inside baffle plate with a 1/2" drill and it's plenty loud enough for my liking. Just something to consider, If you do any long rides, you may get tired of listening to that excess noise. i'm assuming the intake is still stock?