Boeing's MH-47G Special Forces Chinooks are the obvious choice, because Afghanistan's high altitudes and sometimes-hot weather both reduce lift (air is less dense). Which makes it hard to carry useful loads in helicopters like the H-60 Black Hawks. One reason you see a lot of CH-53s and CH-47s in theater, and far fewer UH-60s compared to Iraq.

Special Forces does use some H-60s, both MH-60Ks and HH-60 Pave Hawks. They also have a number of AH-6 “Little Bird” light helicopters, which performed so very well in Somalia during Blackhawk Down. The question is whether any of these models has what it takes for regular duties in Afghanistan, carrying full sensors, plus extra weapons, plus fully loaded Special Forces teams. HH-60Ms might, but that's an engineering question. What has to be acknowledged up front is that it is a question.

One out of the box alternative might be Eurocopter's Fennec (AS 550) helicopters. They did well in tests for India, which has high altitude and heat requirements of its own, and a civilian AS350 B3 version has landed on top of Everest.

These are light helicopters, which means they're not going to be heavily armed and armored. If SOCOM just wants a fast taxi service with good high altitude performance, which can keep its original military electronics (no CAAS cockpit), be fitted with a small surveillance turret and a GPMG, carry about 4 operators each, and be given to the Afghans after SOCOM is done…. well, they would be very reasonably priced. And American Eurocopter does have the UH-72A LUH production line in Alabama, which already builds civilian AS350s for sale worldwide.

On the other hand, “We support reallocating the $2.5 billion for C-17s to purchase 30 new-build MH-47G helicopters, which could be used by Special Forces and be available to help with Combat Search and Rescue duties as a stopgap for the canceled CSAR-X program….” THAT would have had real credibility.