Any of the extensions other than a SuperTruss will require fabrication to mount the side chains. I think you may have to change rear tie downs even if you go with a Curt receiver.
If you decide go with the Torklift setup, get the part numbers you need off their site and search prices on those part numbers. Ballpark prices should be $500 for the SuperHitch, $500 for the SuperTruss and $250 for the tie downs.
When I upgraded my Ford receiver, I was able to sell my old OEM receiver locally for over $100. That may at least take a little sting out of your upgrade cost. This is my second SuperHitch, SuperTruss and set of FastGuns so I am aware that it is not the cheapest option, but it has been the best option for my use.