I've been looking at upgrading the exhaust on the HD now that the camaro is done. I need to keep the factory emissions which are only cats and air. I was thinking of shorty headers (unless there is something better that uses the factory cats), cutting out the factory muffler and welding in a magnaflow and running some pipes over the axle and have it exit out the side after the wheel or a catback.

Any suggestions? I'm looking to pick up some power, mileage and something to do.