Do I need a fuel pump and regulator to use this tank?

Yes. Bottom-feed cells require an external fuel pump and pressure regulator to function. This tank supplies the outlet; you provide the fuel system components that match your engine's fuel pressure requirements.

Will this tank work with a carburetor or does it need EFI?

Either one works. You'll need a mechanical fuel pump for carbureted setups or an electric pump and regulator for EFI. The bottom-feed design just means fuel exits from the tank floor — how you manage pressure is up to your fuel system.

What fastening method should I use to secure this tank in the car?

Mounting method is not specified — inspect the tank base and your installation location before committing to straps, brackets, or fasteners. Test-fit first to confirm clearance and decide whether welding or bolted mounts work best for your build.