The base gasket is metal... the short studs that are used to hold the cylinder down vibrate loose even with a OEM gasket. A metal gasket will make it even worse. Honda used to send spring metal locking nuts with their HRC 250r short track motor kits.Ha that is the kit. This one is not a Niche Industries cylinder, or at least it is not labeled. And I did not spring for the extra air filter. Seemed kinda pointless. But the base gasket is all metal and the reed gasket seemed very thin. I would be curious to see what what an expert has to say about them.