If you get ATs, in 6 months you'll probably wish you'd gotten MTs. Might as well get MTs and do it right the first time.
I have Goodyear MT/Rs on a 1990 RRC (pics in gallery) and have been happy with them. They hum a little on the hwy, but not too bad. All mud tires are going to be noisy. KM2s are supposed to be solid as well. I have Maxis Buckshot Mudders on the D90, thought I'd hate them but they've turned out to be a great tire.
Go up to at least 265/75R16 tho.
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1975 Series III 88" - SOLD
1990 RRC SWB
1994 D90 ST
2001 Porsche Boxster S