A new development from the Race Shop - ?The Indy Series Exhaust? - FOR RACING USE ONLY. Designed exclusively for drag race applications, this 4:2:1 exhaust is the ultimate design for peak power on stock, heavily modified and nitrous engines. Quality, lightweight stainless steel construction. Tapered head pipes and full merge collectors for maximum performance. Slip fit collector joints with ?dual swivel end retention springs? Tuned length megaphone with optional baffle. O2 sensor bung in rear collector for wideband air/fuel ratio monitoring. Weighs only 10 pounds, over 21 pounds lighter than the stock Hayabusa exhaust. Includes oil cooler bypass kit and spring puller tool. Fuel maps available for many combinations. Fits all years ? 1999-2007 Lower fairing modification required, adhesive cut-out template supplied. NHRA and AMA Prostar contingency fund for all Indy Series Exhausts.