Many thanks Stu that is just the sort of info I was hoping for. I also run a Dual Cam. One big thing will be the driving characteristics, so I will have to wait for the Max Payload that is coming in to the dealer.
I do think the brakes will be the biggest issue here. The GVWR is basically the same, just added payload for the weight they took off the truck in '15. NO doubt the 250 will see bigger brakes, but as I said they need that just to stay even. THe better engine braking of the 6.2 is a very good point. Years ago I picked up that advice here and have used it many times to good effect on some nasty descents.