I will be the first to admit that I am not mechanically-inclined. However, after getting my hands on a shop manual, and reading it over, it was obvious that even I can take on much of the maintenance and enhancements.
I recently tackled the M6 after talking with a reliable H-D mechanic. The actual installation of the M6 itself is simple. Getting to that point was another matter entirely! The time invested to get the primary cover off, plus the time to put everything back together once the M6 was installed, far exceeded the time it took to install the M6 itself.
Results? Definite improvement in shifter performance - from the famous "clunk" to more of a "click". Finding neutral is a piece of cake now too.
I guess time will tell regarding chain life and the maintenance of proper tension. But we are off to a good start!