The LPR wheels/tires are about the lightest available. Whatever you do, do not scrimp on battery quality. You may want to try some of the new lipos Mike has been selling, they look good.
I've already got the LPR's, they're probably half the weight of the stockers. What gearing would you recommend? and who has the best lightweight lipos? Is there a spend-more-to-weigh-less option?