Ian's post clears the cost subject up quite a bit.
Re the 53K vs the 47F, a few points:
1. Max gross. 88,000 vs 50,000 lbs.
2. Installed Power: 22,500 vs 9466 SHP.
3. Fly-By-Wire: Yes vs No.
4. All New Aircraft: Yes vs No ( modified older models in most cases for US Army anyway ).
5. Cargo Hook Limits 53K has 36K Ctr and 25K Fore and Aft. Several values noted for the 47F, but all were appropriately lower.
These are just some of the factors facing prospective other customers for each. Politics and fleet commonality/maintenance organization/spares commonality are always in the mix. Some might say that the installed power and weight put the K in another class.
Almost forgot: Re the 53E vs 53K empty weight question: At the moment the 53K test aircraft are in what is termed development/qualification flight test. Some people assume you simply design the machine, do a first flight, and then transition into the qualification testing phase. In reality, the first phase of the process is typically called " development flying. Establishing the speed, handling and maneuver envelope etc. In the helicopter business, this phase of testing invariably uncovers problems, 100% of which add weight to the previously sacrosanct empty weight bogie ( target ). Obviously, if there is enough weight growth, a weight reduction program is the typical response. I should add that I am not involved with the program in any way thus I have no idea where they are on this subject. In summary, at this point in the K flight test process, putting an exact number on weight-empty is premature. Its also worth keeping in mind that because of the technologies applied to the K, some areas have benefited from significant weight reduction ( composite tail, composite sponsons, composite main and tail blades and Fly-by-Wire controls etc ).