My advice is not to go that path.
Either use the Tak stock focuser, which is fine for many, or upgrade and swap it out for a fitting full Starlight R&P focuser to your liking. Expensive but worth the cost if you need it's functionality and/or are in love with it's feel.
Just use it a couple of months under the stars first, then decide if you need to change anything. Chances are you will be happy with the FC-100 as is.
I foolishly "upgraded" my 2.7" Tak focuser on my FS-102 NSV with the Starlight Feather Touch Micro Pinion Assembly. It is definitely not the same as a Starlight focuser.
A better upgrade for just your focuser pinion assembly would be the Tak micro focuser, if any. Or go all the way with a FT R&P focuser.
Just my 2 cents.
What did you find less than ideal with the Feather-Touch micro pinion? I have had a few FTF focusers and they are excellent focusers for visual work, extremely fine focusing with minimal shift off axis during focusing. Not as true running as a Moonlite but very good. My big Moonlite refractor focuser runs the entire 4.5" of travel with virtually zero shift over an 80' laser run. The FTF with 2.5" travel was not even close but in practice there is so little travel used it doesn't matter.