Low to mid 60s on the chips, I haven't paid much attention to the board temps, but cooler than that. 10 degrees or so cooler? It'll depend on ambient temps. I've been doing this in the fall, and the temps rise on warmer days. I'm sure people here who were operating during the summer dealt with higher temps. The fans speed up to deal with heat, but if the intake air is hotter, there's only so much the fans can do.
FWIW, I suspect this stuff is pretty sturdy. So long as the temps are fairly stable, it'll probably be fine. A bigger problem than running a bit hot would be lots of big swings in temps as components heat up/cool down and wear out connections with all the expanding and contracting. Good luck
