I'm in Hendersonville NC (home of Ohlins USA) for work on the NIX suspension and shock of my F800GS. I just spoke with Gary Christopher, Ohlins USA Service Advisor for motorcycles, regarding my own bike's issues, and when we finished, I asked the very questions being posed here, especially in the context of the title of this thread. Take note. The forks do not have to be machined as of course. On the other hand, the Ohlins NIX cartridges are not "drop in." Adjustments to the OEM forks are routine to enable proper fitment and operation of the cartridges. These adjustments might be, as he called them, "no brainers" to experienced and equipped technicians, but fitment cannot be accomplished by simply "dropping in" or "bolting on." He summed up that this will be especially true with the new forks on the 2013 F800GS because S&W is notorious for variations or inconsistencies in their production. Alas, the technician who was to do the work on my bike was injured in a crash in a moto race over the weekend, so I'm waiting to hear if I'll be heading eight hours home without the Ohlins work being completed. I'm optimistic, though. Fred P.S. The work was completed after all, and I've been having a blast on a much-improved ride, on and off pavement!