pretty much as Kev has already mentioned mate.

engine mounts are a common weakness if the cars lowered a little to much.

drive shafts can destroy the inner CV joints if its been driven like an animal with silly launches.

and as for the front prop going, be gratefull that it only takes out the side of the gearbox when it lets go if thats what it is, when they are spinning at the stupid RPM's they will chop thru everything - and its only inches from your feet!!!!