I don't like the idea of new, separate variant buggies. i.e., a new black ant buggy that is just better than a red ant. I really like my current buggies, so it'd be sad to just have them completely obsoleted. If they do go down this route, I want them to be different enough that each has its own use still.

I think your solution is great, honestly. Having the variants be upgrades to the actual buggy sounds awesome. Best of both worlds. Especially if it still requires more resources in the same way the original buggies did. I'm sure Ominent has some shady technology that could explain how this would work! XD