You can for get your IRT sensor, leave it home and save your bag space. When they do overheat and overheat "ONCE", then it's pretty much all over, you warped the head on a 660.
I'm sorry, this is a bit over the top, unless your definition of overheated is different then mine.
I bought my TT new in '04, it's very close to having 9,000 miles on it. It's over heated quite a few times and there's zero sign of damage. Now if you got it hot (light on and it in "limp mode") and just kept pounding away on the trail then yes, you could do some damage pretty quickly.
At first I used to just stop, pop the hood and wait. Later on I found that just jumping off the trail/running on the side of the trail where there's loose snow would cool the machine down very quickly so if I could that's route I would take. It really doesn't take much.
I would go an entire season with out my TT overheating, then the next year it would seem to be an issue all the time. The colder and harder packed the snow the wore it is. On a 40 degree day when the snow is soft I can run all day no problem, -10 watch out!
Usually on those -10 days it was only a problem early in the morning, after thing warmed up a tad and more sleds hit the trails to bust up the packed snow things where fine.
Scratchers made all the difference for me though. I just keep an eye on the gauge on days I think there's going to be an issue, if the temps start to creep up over 180 and stay there I use them. Pretty simple, no overheating since.