What these guys are saying about DID X-Ring and steel sprockets is 100% spot-on. I'd consider JT steel sprockets too.
For tires, it's preference. I always preferred more side-wall of a 22x11-8 (or now-a-days more like 21x11-8) and with the higher rollout compensated by dropping about a tooth in the front (so 12-39 on a stock cyl motor) - which gets you back to about the same overall final ratio that 13-39 would have with a smaller rollout 20x10-10.