My modified Go Tech 5 port runs best at 120-135 so i wouldnt worry about temps too much, if its going hard and still blowing smoke then you have nothing to worry about. I run 25% nitro and 15% oil and on pull down its in great condition.

Yes these motors run better hot and for the price even if it wore out a bit faster than most engines the power and revs i get out of mine are simply amazing IMO.

I get 10.5 mins out of a 125cc tank using standard Hyper 8 Pro exhaust, seems to work very well on the engine.
Swapped to an OS Vspec other day for a triai, gained more bottom end but doesnt have the top end power revs that the Go Tech puts out.