Im going Deaver route as they are supporting my Ultra 4 build plus I figured go to the people who build parts for racing in the desert right? So far I have no experince with Deaver but they are a great company and great people. Im going with there 4" "race" leaf pack to handle the desert at speeds while still offering flex and control in the rocks. We will have a full size spare (35x12.5x17 MTR/K on raceline beadlocks) 16-22 gal fuel cell (not sure on the exact size yet) full cage (1.75 x.120 wall) and spare parts and tools and we were told the Deavers will handle it all very well. Best of luck, If you need contact info may be able to set you up with a good Point of contact. let me know.