This feature is not possible, hitech has mentioned that adding GV collisions would cause massive problems to the game-play. The problem is the internet connections, usually you do have some packet loss in games causing a slight bit of lag or warping, nothing serious. Yet warping with the tanks would mean getting a bit too close could cause you to warp into another tank sparking a collision. And I think I heard it can cause the game to crash when two tanks collide with one another, in one another.
Either way, I heard someone saying that the GV collisions feature was tested and found to be full of bugs and therefore isn't being released.
