the z22yh is slightly thinner than the z22se and better quality - both are double layer
the z22se can cope with 500bhp, but the last few GM gaskets I've seen looked cheap and cheerful :silent:
the saab / z20net is a triple layer gasket and will lower CR slightly (and looks identical to the cometic gasket)
I have a z22yh on my high compression NA engine
ps: the z22yh head gasket on it's own is approx £45