[swordtart]

Also these could be three men in a garage knocking out custom vehicles, one of which got lucky in a regional final once. There doesn't have to be a manufactory producing thousands of that vehicle behind it, anyone can make a one-off custom design due to the standardised parts.

The Chassis + Suspension + Plant combinations are more limited and these might well be manufactured in the thousands by big companies, they just don't put their badge on the car that is built on them. This makes economic sense as fitting the plant is a more difficult job (and it is often the single most expensive component). Also the chassis limit pretty much determines what your plant needs to be and this further limits the credible combinations.

Every other component can be an after-market fit. Armour can be readily changed and that is what will set the "look" of the vehicle. Weapons are easily swapped in and out and they determine your combat performance.

This was the way it worked in the early years of motor vehicle manufacture. You bought a chassis and got another company to fit the coachwork to your personal specification. It was Ford who came up with the standardised design and that was only so that he could mass produce.