The composite gasket is usually the "no-retorque" type, which saves a little time during engine assembly. The solid copper or steel gasket needs to be torqued again after the engine warms up. On the very high compression race engines I build, a solid gasket is an absolute necessity when the compression ratio gets above about 10:1, and the blower engines use a stainless steel O ring to seal compression, and a copper shim gasket to prevent water leaks. Unless you're going for extreme perfrmance, the composite gasket should work fine for street use.
Jerry
