Jared Downswrote a review of DT Swiss Star Ratchet Upgrade Kit on May 25, 2018
Familiarity: I've put it through the wringer
I swapped an 18T on my Yeti SB5,5 for a 54T and am mega happy with the faster engagement.
This is super easy to install. No tools required if you have a quick release axle.
Just make sure to go easy on the grease. Too much grease is a bad thing. And with the finer teeth on the 54T, too much grease can cause the teeth to wear out faster.
For applying grease, try finding a small/fine paint brush to get an even coating of it in the hard to get to parts.