Year: 1995-2005 Make: Harley Davidson 1995-2005 Harley Dyna Fat Cat Details: 2:1 Fat Cat is a stepped header system at the head is 1 3/4" to 1 7/8" at collector and 2 1/2" where the muffler goes to the header. All D&D full systems are equipped with heat shields,exhaust gaskets, bolt kit and baffles. Each exhaust system is designed and dyno tested in our facilities. All of our testing is done with Harley SE Tuner. Every pipe is designed to increase low-end torque and horsepower. Performance increases are about 8 to 10 percent with the proper tune on the bike. 525-31-32 does have 18mm 02Bungs in the header pipe All Dyna's have to be tuned with the full system. Baffles Louvered baffles are for 80" to Stock 103" motors Perforated Wrapped baffles are for Stage 4 103" to 113" motors The inter core of the Louvered baffle is 2 1/4" The inter core of the Perforated Wrapped baffle is 2 1/2" Notes: Using Woods cams for best performance use Perforated Wrapped Baffle. At idle, the motorbike is deep, boomy and full of character. Not only does the pipe look good, it is a wonderfully sounding experience for the rider. Blueing and Discoloration are caused by Improper Tuning and will not be covered under Warranty D&D Performance Exhaust Systems are designed for close course racing applications only. Not for use on pollution controlled vehicles.