I couldn't decide on the colors either. The picture below shows the same helo without all the action. I gotta think it's a gun metal gray. I just didn't like it. It seemed to washed out when I applied it. I did however implement that color to the engines. My transport box is black which looks really good.
Make sure you modify the cockpit seats. If you leave them be the guys will slide down and around. There is enough room to throw some seats in there with back pegs to keep them in position.
http://img175.imageshack.us/img175/...rahornetzu3.png