most of what we're seeing is light front end damage.
in Michael's trailer, we don't see the car getting damaged, but there's a lot of mayhem going on there so i can easily buy that he's tapped something with the nose of the car.
in the gameplay trailer, trevor evading arrest:
* trevor's hood isn't popped (some ppl are seeing the shadow of the bulge in the hood - that truck doesn't have a scoop)
* the police car directly behind trevor has an open hood.
a few frames later:
the first police car behind trevor has a popped hood.
only the car directly behind trevor has been trying to nudge his rear end out of line. of course it's taken some damage.
it's headlights look damaged:
if you are not sure that car is damaged, look at the third car back in this scene:
its bumper cover is come off on the driver's side, and its headlights look in similar shape. the 2nd car back, however, looks like it has so far avoided any interaction with trevor or telephone poles:
see how its headlights look different? glass still intact. funny how all these GTA cars have glass headlights and it's so expensive to get glass ones for my actual car in real life.
hoods popped open? rear end collision i guess. we zoom in on trevor while the chase has already been in progress. but all i'm really showing is that open boots and bonnets are linked to light collisions.
does that explain this?