Those titanium shields that go behind the pads might help with heat on the dust boots, too. I put some on mine for the hell of it a little while back:
Hard Brakes - Titanium Brake Backing Plates, Brake Shims, Brake Heat Shields .
Car to car contact is really really rare in an HPDE-type track event. Everyone's generally really careful about passing, and perhaps more importantly there's no winner or official timekeeping, so there's no reason for aggressive jockeying for position or anything.
Spinning out (and possibly spinning off) is going to happen with some regularity overall, it's rare a day goes by at MSR-H that someone doesn't spin in some group, usually more than one person. With the guys I run with, they have a 2-spin rule: first spin they black flag you into the hot pit, check under the car, make sure you're coherent and ready to go back out, etc. Second spin in the same session and they take you off the track and you miss your next session as well. I imagine if you repeatedly hit the two-spin rule you're going to get bumped down a run group, etc...
How dangerous a spin is depends on the track and on the other drivers. Look for tracks with generous runoff areas. Of course, there's always risks, but really you don't need to spin out to learn the limits. If you're spinning, you're doing something wrong (or had some freak mechanical failure (e.g. tire falls apart mid-corner)). Instructors will talk you through slowly raising your speed as you learn to apply better techniques and read the car's feedback.