If you plan to do a slip on for 06-07
If you are planning on installing a slip on that attaches at the catalytic converter (removes the elbow pipe with the exhaust valve) and your bike has more than a few miles on it you would be well served to see if a dealer has Kawasaki part #11060-1330 in stock. It is an extremely thick exhaust gasket that fits over the outlet of the catalytic converter and into the elbow pipe. In the past I mostly reused gaskets but this one was baked in place and wouldn't come out intact. I tried to make a gasket with high temp exhaust repair materials and it only lasted 400 miles. Nothing in the instructions with the exhaust indicated you would need a new gasket either but if I was going to do it again I would buy one up front and install it the first time.