Your R's seem a little low. G62's need to turn up over 7,000 on the ground to get max power out of them. If you're running the stock muffler, loose it for a B&B and pick up 500+ rpm. I was running mine with a B&B muffler, Mejzlik 22x10, and getting 7700 rpm. I was getting 7200 with a std. Zinger 22x6-10.