Check the M-unit and electronics forum.
Many riders have installed the M-unit and love it. From the questions asked in the forum, it seems like it may be a bit tricky to get hooked up and working properly. Particularly if you're not familiar with the circuits or with doing wiring.
I haven't used one but I have rewired a few bikes (cafe style and choppers) with minimal harness. The minimal harness isn't very complex even if you do have turn signals. You basically have a battery and charging system, switches, coils & points, horn, head and tail light, and instrument lights. Only a few wires are needed for all of that. Search "Santee Box" for an idea of what's needed.
Honda made it pretty complex to have added features - multiple fuses, turn signals that are also running lights, the neutral safety system... and the really complicated parking light circuit.
Using a simple on/off key switch with one fuse eliminates a lot of wire and complexity.
If you find the Honda wiring diagram daunting, check out a 70s Italian bike's. Or don't, it will just give you a splitting headache.
With an M-unit (or similar) it looks like power plus all loads and switches get wired directly to the module. Not difficult but the harness wiring isn't designed for that, wires pretty much go from switches to loads and don't necessarily go past where the module gets mounted. I think you would want to make up a new harness specifically for the M-unit. I would have no problem doing that, and would use appropriate high flex wire with cabling tape.
