5-6 point harnesses with a guide bar or truss is fine, as long as you still have the stock 3 point belts for use when on the street.
Good brakes, good brake fluid, good tires, proper tire pressures (you’ll have to figure those out trial and error style), your own helmet, all mechanical components in perfect working order, and the proper attitude are all you need to start. “Mods” should come later.