Heya,

asked the same question a while back, as far as crashing into others, or, others crashing into you, there's now guarantee anyone is insured (stated on most sign on liability forms), so, it's helmets at the ready trackside or back in the pits

Not sure about damage to the track itself, I am pretty sure the nurburgring charges for damages and recovery, dunno about others.

Hope this helps, like you I am interested in taking part in track events, others on here have done it extensively so should be better able to help