I got cometic gaskets once for a 440 XCR. The stock head gasket is embossed metal(thin), the cometic replacement was a thick composite, which would have lowered compression. I had to spend more money for a good Polaris head gasket. Stay away from Cometic.
The stock Polaris gaskets are the best. I don't know why Wiseco uses Cometic gaskets in their piston kits. The o-ring style head
gaskets would'nt fit on my XLT- even when I froze them outside at -30F. I just reused my old ones for now. The Cometic base gasket
wasn't even close to the quality of the Polaris gasket either.