It has been done on this forum but I can't seem to find it. Wish they had a decent search mechanism for it.
Bottom line: a 16T front sprocket screws up the firmware of the traction control unit. Bummer for me because I used a 16T on my '11 and '14 Ninjas to good effect, especially in the 80-85mph cruising range. I just picked up an '18 but haven't had a chance to test yet. The '11 and '14 had quite different vibration modes and they varied with mileage. The '11 started out vibey and smoothed out with age. The '14 started life smooth and became vibey. I did the usual; re-torque engine mounts, gel grips and rubber washers under the gas tank mount and it helped enough to make the bike comfy enough for long rides. Still get blurry mirror images, however.
I'm including a little table I did for the 2011 Ninja to show how much gear changes and a /55 tire change affects rpm. Note, after 2014 the speedo takes off the ABS sensors and is not affected by sprocket changes, only tire profile.