I think they only changed the rear stock w/ a GP crane and and did some re-wiring to get rid of the battery PEQ.
You should just buy a VFC and a GP crane stock, and bring it to a remote control car store to let them do the re-wiring, should cost you around 20 dollars for parts and 20 dollars labor.
But the HK416 is out of stock in many places, you might still find the DX version tho...
P.S. I think that unless you live overseas, WGC will not do business w/ you.