04-09 Yamaha YFZ450 Spiral Core Full Exhaust System

Performance: 20% +HP increase with open airbox & performance air filter, 24% with Velocity IntakeExcellent throttle response, unbeatable mid-range and over-rev power. Spiral Core design: More Power / Less Noise, 1.875 inch spiral perforated core for better sound dissipation in a wide open design. That equals maximum power gains with less noise than other open pipe designs! Competition-Stepped Headpipe: a full system for a big power increase. Short and Fat: 11 inches long 4.5 diameter At 11 inches long it's keeping the weight down, with over 1 inch of soundabsorbing packing depth throughout the design. Tough .120 wall thickness aluminum muffler is designed for "collision resistance" to last the life of your quad. Lifetime Warranty- protects against defect in materials and craftsmanship.