Vance and Hines slip ons would be a great option. Mine are 4 years old and still look great. I pulled the baffles out and took the packing off and put them back in. You will likely have to rejet. I'm in PA and run about 400-2200 elevation. Your mileage may vary depending on where you ride. The sound is deep and throaty and comfortable at cruising speeds. You will appreciate the increase in performance also.