Paragraphs man, paragraphs.... You get points for the use of a periods, but no paragraphs, commas or caps gets you a couple demerits in my book for "difficult to read" content and thus I'm less inclined to help.
So you're running a 7M-GE then? Cressidas came with other motors too. (durr.... gotta remember what the title said... durrr. Sorry.) If it's a 7M then feel free to post up in any MKIII Supra forums, that's the generation which ran the 7M.
The gasket in the thermostat housing is an O-ring which wraps around the thermostat itself; kind of a reversed grommet. If you're leaking and the grommet is new then you need to check the mating surfaced for irregularities in the surface or warping. If you just can't get it to seal, a very thin film of FIPG isn't going to hurt it.