TAB Performance Black Dual Shorty Slip-On Mufflers 111-2042 8-12 hp increase over stock exhaust 15-20 lbs lighter than stock exhaust Install 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.