Most of the turbo and supercharger guys I know (myself included) run either the 9333 pt1 (stainless ring) or the 8548 pt2 (tin ring) with great success. Both have been proven to hold under boost and have been run with great success. They will also ensure you still have a "fuse" so to speak against detonation. Keep in mind, it's not necessarily a bad thing to blow a head gasket due to sever detonation.