Best economical tuner out there is the new FP3. Needs no dyno tuning cause it has auto tune feature owner can do and it's controlled via your smartphone through their app. IF YOU JUST CHANGE SLIPONS NO TUNER NEEDED BUT WHOLE EXHAUST SYSTEM YOU NEED IT. Fuel is a cooling agent so running engine lean for prolonged periods will overheat. Bad idea for air cooled vtwin. EBay has FP3 for just over $300