I bought my '91 in '01 and it was already at 90k with some track miles (so, about 9k miles/yr). I then put 90k miles on myself as a DD in about 10 years, including about 25k+ miles of Canadian winter driving at temperatures that you wouldn't even go outside in yourself. Plus I've added some autocross and road course track miles of my own. So, from my personal experience, 100k with good maintenance records is no problem at all as a DD.
In fact, I'm on the belief that the more often you use the vehicle, the more the parts get used/exercised and the less issues you have with parts drying out and cracking. The more you use the a/c, the more the seals get lubricated; etc; etc. And because of the 90k miles major service interval .. and the fact that people shy away from 'sports cars' with 100k miles on them, you can usually get a pretty good deal once you get into the 100k range. If you can find one with 100k; with the 90k service recently done; and a new clutch at the same time; with good maintenance records .. buy it.