Will these work on my wheels?

These are M12 x 1.25 thread pattern — that's the standard for most vehicles, but confirm your stud size in your owner's manual. The extended length is designed for deeper wheel offsets; if your wheels sit flush with factory spacing, standard lugs work fine.

Do I need to replace all 20 at once?

You get 20 pieces so you can do a full wheel set with spares. Most vehicles need 4–5 per wheel depending on bolt pattern. Buy what fits your wheel count, or keep the extras as backups.

What torque spec should I use?

Refer to your vehicle's service manual for the correct torque value — aluminum lugs and steel studs require the same spec as your OEM setup. Over-torquing can strip the threads; under-torquing risks wheel separation.