All vehicles are currently unaffected by the recoil of their weapons. Even the heavy Merkava should exhibit rocking on the suspension when the gun is being fired. Especially light vehicles like the T-100 should be affected by their guns.

Videos:
https://www.youtube.com/watch?v=tj-a9dfflyc
https://www.youtube.com/watch?v=qO3Aj0OUvtk
Last one shows even AA vehicles being pushed back by the recoil of their weapons. When firing horizontally, it would actually push the tank back until the brakes on the tracks held.

I am also told that firing combat ammunition will move a Leopard 1 back about ten centimeters on concrete surfaces through push of the recoil. This is actually represented already (At least sometimes, Tanks will be slightly moved sideways from the recoil of their weapons.)

Lack of physical shock on the vehicle itself is not nice, though.

Please, if you find the time, implement this now that we have physx.