I'd still shoot for the coil wire if you could get at it. Again, tough but you could keep a wire in your frame or bumper pretty easy. I was trying it with a bit of the wire they use to tie up chain-link fence. Looks very possible. You need a good length of it and again, a good light but it looks doable. Not sure if this would damage the vehicle or not.

Stopping a car with a firearm:

Pistol:
Occupants (depending on situation)
Tires
Radiator (hot day in LA, speeding car - it won't stop instantly but it'll stop quick).

Rifle:
Occupants (again, depends on the situation)
Engine block or transmission (once the fluid is gone an auto will obviously not be movable)
Radiator

Pistol assumes a patrolman in an 'oh #@$' situation. Rifle assumes a marksman with at least some time to make a shot. LE and Military will have different views on the subject...

(/hijack)