Hello.

You do understand that your controls are probably in conflict with other controls of the game. When you change one control you must make sure that other aren't in conflict with it.

Also is there a reason you want to bind your vehicle controls to a mouse?

The controls have been pretty stable and without problems for quite some time now and we do not plan to make changes to them.

It's been no problem to control vehicles with your mouse before. There's no conflict between controls (as the problem is the intended behaviour - "Car Left" and "Car Right" are part of the direct control system).
The problem is that controlling your vehicles with a mouse (i.e. the steering) is now no longer possible without a major hassle, as turrets are controlled with the mouse as well.
You can now either control your vehicle with the mouse or your turret - but you can't have both, because you will automatically steer your vehicle when you move your commander or gunner turret with the mouse.

"You can now either control your vehicle with the mouse or your turret - but you can't have both."

Well of course, if you bind both on the mouse of course they are going to steer together.

You have to change the Aim controls as well for it to be not in conflict.

You can either control the tank via mouse and the turret by keyboard. Or you can have default setting which is mouse turret and keyboard for turning the tank.

Instead of Car left, Car right use Car more left, Car more right.

Car more left and Car more right have a distinctly different behaviour than car right and car left. I state again: I know that it's intended behaviour - I'm not that daft.
The problem is that this intention is in the way of the direct control system to work properly if Car Left and Car Right are used for mouse steering.