Rams n’ guns n’ armor. All the bits and bobs mean nothing if your “deathmobile” can still be torn apart. After that, probably life essentials (food/water). After that, probably engines and batteries to ensure it can move through hordes from a standstill, and do so fast. Then crafting gear, then cargo space. S’how I’d do it, anyway.
Composite armor. Milspec vehicles.
Are you driving around things or through them? If the former, maybe err on the narrow side. If the latter, build a spiked block or ball with enough room for what you want, for all it matters.