Well I don't think there really would be much stopping you from doing something like that in real life(other than stupidly restrictive laws like we have here and all the electronics, but in beamNG you can also remove traction control and ESC which I think would be one of the major things that would cause problems but I honestly have no clue about electronics in cars or much about cars other than the very basics) as far as I'm aware, so it might not be impossible to do in real life but it would be extremely expensive, pointless, and stupid, but maybe possible. If it's stupid but reasonably possible without doing anything too crazy it's realistic enough for a game that's about realism IMO.
Actually, on most cars you can sabotage the TCS, ABS, ECU, and so on simply by pulling the appropriate fuse. Pulling a fuse is one of the easiest ways to mess with a buddy's car. Not that I would have experience with that sorta thing... ; )
How about making seats out of lots of other parts , most of the time the seats explode in a weird way with spikes from it. So how would that be if the seat is made out of lots of parts so that it can break apart or something like that. And I swear a good car accident looks way better when the wheel which was in the collision has no tyres showing- so maybe the tyre could rip and fall off or something similar.
