Model made in blender by me.
This mod adds a new car prototype called SA-mauler that has a machinegun flamethrower, optional sized equippment grid and multiple options including:
HP amount and Tree Immune.
This car heals itself when colliding with biter nests, worms and trees, you can toggle more including these in mod settings.

Settings I recommend are:
If heal with biters is on then: Tree Immune Off, Healing at 0.25 for a challenge 0.35 for getting accustomed to it.
If heal with biters is off then: Tree Immune On, Healing at 0.35 for a challenge 0.45 for getting accustomed to it.

For reference the car has rocket fuel here