It's very unconsiderate to make statements based on false assumptions. The difference in the compression rate is not made with the head gasket thickness. The ST170 gasket is on the order of 1.0mm and the other 2.0 gaskets, including RS, is on the order of 0.6mm thick. The thickness should be chosen so that the piston crown to cylinder head plane distance is optimum. Usually this is between 0.7-1.0mm depending on application. If you then end up with the wrong compression ratio, then you have an unsuitbale piston dish/dome volume.