I'm sure this came up before ... think I responded at the time.
I fitted a GPI-DS (Healtech) to my CBF600SA, just need to find the diagnostic socket (DS) and it plugs in. Then you have to route the cable to the instrument area and choose where to stick the display. Once fitted you run the bike and go through the gears while the GPI 'learns' the gear ratios. Easiest to do on a paddock stand but you can do it on the road. I think someone else reported back where to find the DS, from memory under the seat general area??
The advantage of the DS version is that you don't cut into the wiring, which to me is a pretty big advantage.