I say look for any reason at all to dump the 8800 series gpu's (and I just bought 2 new ones off newegg for 70.00 each) Just no reason to put up with such high heat output when the problems have been solved with the 200 series gpu's. Now if you want to modify a 70.00 gpu with a 45.00 aftermarket cooler, do the math and see what you can move into.
My 8600's 9600's 8800's are all high heat output gpu's, but they are good ppd producers for folding and the price is right, just a trade off on heat. I will not cry one tear when one (or all ) go belly-up.
Point of reference, my 275 folds at 69C in the same room my 8800's hit 89C