> can anyone give an accurate thickness that a
> 2mm hks head gasket compresses to please
The 2mm is the amount you use for your computations. Since it is metal, it compresses very little, if any at all. And don't forget that the bore of the hks gasket is 91mm vice the 89mm of the stock gasket.
For others, here are the other thicknesses. The 1mm HKS is of course 1mm thick, with the 91mm bore. The stock gasket's compressed thickness is 1.2mm, with an 89mm bore.