UF-MV21-AL:
Formerly known as the AS-MV21-AL. This is an armoured car, designed to be maneuverable in tight quarters and offroad. The frame, armor and engine block are all built from aluminium for reduced weight. It sits on four big tires, the rear ones shrouded by armor, on hydropneumatic suspension. It is powered by a V-6 motor, which gets it up to 70 KPH on a good road. Its shape is tight and rectangular around the crew cabin, which holds only a driver and gunner, to minimize the quantity of armor needed. The engine is in the rear, and includes the lightest (thin) armor in the slats over the radiator. The front armor is medium and most of the armor is light. A belt-fed UF-AC18 gun fires from the top of car, with the gunner's hatch open. The gunner hatch acts as armor to each side when open, but the gunner is still somewhat exposed compared to a tank turret.
Enlarge and reinforce the tyres and wheels and lower the chassis relative to the wheels(but maintain it relative to the ground) and review the suspension, especially with regard to withstanding higher speeds.. This will add stability. It will be bad for uneven terrain where the chassis could land on a rock or something but over flat country such as farmland it should be able to blaze along without a care and roads should be largely irrelevant. The objective is "off-road" not "all-terrain". We are being opportunistic here, we can't hope to get something that can deal with all enemy action, so lets just take the ones in open country. We can carve dirt-tracks through the heavier country if need be...
It has a tiny V-6 motor, replace it with one of the fuel drunkards from the air-force(I am thinking of the one from the bomber, that sounds like a monster, but the interceptor's engine sounds like fun too, can we turbo-charge that?). The engine is rear-mounted with the cargo space, so if we just cut a hole for it then it should be possible to jam the thing in there. We may need a roof-mounted radiator or something but that is just pipes, so shouldn't be too much hassle.
Throw on some mounting points for tiger infantry to be mounted on the rear and held in place with quick-release harnesses...