Will these fit my factory wheels or only aftermarket?

M12x1.25 is a common metric thread standard across many manufacturers. Check your current lug nut specs before ordering — if you're running the same thread pitch, these swap in directly. If your bolt pattern differs, these won't thread properly.

Do I need to replace all five lug nuts per wheel or can I use what I have?

This 20-piece set gives you four per wheel for a full set of four. Mixing old and new nuts is fine functionally, but you'll lose the uniform gun metal look unless you swap all of them out.

Can I paint or powder coat these after I install them?

Yes. Once installed, you can mask and coat them with automotive-grade paint or send them to a powder coater. The aluminum accepts both finishes well — just avoid extreme heat cycling if powder coating to prevent adhesion stress.