Ignore that entire post.
I did exactly that some months back and nothing happened. No, it wasn't with a Standard rally car, either, but was a Premium. I even tried a few of them, all with the same results. Their parts would start to flop around but would just continue flopping around forever. I tried it with and without mechanical damage turned on.
I'd run head-first into oncoming traffic repeatedly, even crippling several of their cars so badly that they couldn't even limp to the pits for repairs, but nothing fell off of my car. After a while of going against the traffic, I tried for side impacts, moving back and forth across the Daytona banking so that cars slammed into my side at full speed. Nothing worked. I did this in several half-hour sessions, with different Premium rally cars, sometimes with mechanical damage on and sometimes with it turned off (mechanical, as in "effecting performance"), and nothing ever fell off after hours of trying.
I then went to Eiger Nordwand, went in reverse to the tunnel, and parked so that I was in the middle of the track, perpendicular across the road, and waited for the cars to come to me. As soon as they slammed into me, parts fell off. It only took as long as a lap of the circuit.