i replaced mine with a new toyota gasket, correct me if im wrong here people, but the thickness of the gasket depends on how much material you remove from the block and head surfaces to bring it back to stock compresssion,, and or,,, you can get a thicker gasket to lower the compression ratios for higher boost potential.
some metal head gaskets are good, but require specific surfaces for proper sealing against the head and block...
also if i were you, id also call around and find a good machine shop to look at your head when you get it off to check for warpage. valve adjustment and or lapping the valves even valve guide seals ecetra.. if needed or whatever..
PS;ask if them have adjusted bucket shim valves before, if they say what? keep calling around..
http://www.supra.co.nz/87tsrm/
http://groundsky.co.nz/techinfo/TSRM/
http://groundsky.co.nz/techinfo/TSRM/03_EM.pdf