THe Memory cap for this system lies at 6Gb, but that 4Gb SO-DIMM is rather expensive. I already run Snow Leopard which took a full 2 degrees of the max back-then... but that's it.
SMCfanControl is currently running automatically at startup, and helps keep the heat down once it's there, if there's no real cure for the issue, I will let it slide, so long as that G86 chip doesn't go bad on me, it's no real threat to my health.