ive had a few PM's lately asking about metal head gaskets (mhg) for the 7MGTE 7MGE 7M-GTE 7M-GE (yes im including all this shit so people can find this thread with the search engine)
anyway, below is a (BIG) pic (no photoshop - again!) of a HKS gasket demonstrating its laminated construction. you DO NOT use o-rings with these kinds of gaskets.
However , copper head gaskets (another kind of mhg) require orings withou question - copper is soft and maleable, and requires the extra clamping pressure around the combustion chambers provided by the orings in order not to blow