Harley Davidson Night Rod/Street Rod Turn Out Exhaust Pipes 8-12 hp increase over stock exhaust 10-15 lbs lighter than stock exhaust Installs in minutes with only a few simple tools Blueing and/or discoloration is not covered under warranty, it is a result of improper tuning, cam timing, engine timing, jetting, overheating etc. It is not caused by defective manufacturing. The mufflers and components offered may not meet EPA emissions and noise guidelines and may be restricted to off-road use only.