Ok, so I am most likely going to get laughed out of the park for this question. But hey, I saw Greg Minnaar on a hightower with what seems like a fox 40.
Certainly i am not a dh legend, not even close, (although i did own v10.5 until recently) however it did get me wondering what needs to be done to a fox 40 to bring it down to the 170mm travel mark.