s13 redtop sr20det. Greddy, Tomei, Nismo etc. What makes them so special? They advertise as being metal and you can select your thickness. But are they really stronger than the oem headgasket $80. My stock head gasket is fine, Im just upgrading my turbo, will be pushing around 18psi. Just wondering if they are nessesary for that much boost. Or what's the maximum boost/hp for an oem hg?