You can get a 360 around there.
(actually cheaper, 60k is lowest I've found listed : http://www.autotrader.com/fyc/search...=1294769525410
Yes, 430 are about 120 for the cheapest ones.
It won't be too long till the ones going for 120 fall under 100.
("scratching at" was meant like "getting there", more than "is there")
360 is the 430 predecessor for that market segment.
Look at the 360 prices and ages, you can expect a 430 to be around that price when it's of similar age (not that long of a wait all-in-all).
Personally, if I went for it, I wouldn't worry. Life goes on.
Worst that happens is you spend some cash, hate it, sell it, get something else.
I guess the 90k price point is still a good fit for the GTR.
Other options : used 997 or used R8.
All good options.
I suspect the 997 is the next cheapest to maintain (just because it's so common).