X2 Phil, my 2012 was upgraded by FR to larger tires and new front axle air bags, with the front axle recertified from 10,400 lbs. to 12,000 lbs. I believe that FR will do that upgrade for the asking.
As for the 340hp vs the 360hp, the additional HP is via a simple chip change. The Allison 3000 is the big deal. The 360hp has a 12,000lb front axle, for which the 340hp can be upgraded. The 340hp has a rear axle rating of 17,500lbs and the 360hp is 19,000lbs. I have done extensive comparisons of the rear axle's parts for both versions, at the Daimler web site and couldn't find any differences. So, is the rear axle specification difference a marketing ploy???
The 360hp for sure has a larger toad capacity (GCWR) because of the Allison 3000MH. However, although both have great cargo volume capacity, they both are marginal in weight carrying capacity - that is why you should get you rig weighed, fully loaded. RIVA came up with the OCCC rating (Occupant and Cargo Carrying Capacity), but most manufacturers will not show that specification because it show how little you can carry. - Hank
Gale & Hank- 2012 Berkshire 390BH