I'm having solid 120FPS in Infinite but seems that twhen I pan the camera it stutters but only if I'm moving. As long I'm stationary the camera will move butterly smooth but as soon I move it starts to stutter.

Try the solutions provided by this web if they can help you.

https://pcgamingwiki.com/wiki/BioShock_Infinite

None of these work, nor do the ones 2K has on their official website. The only fix for me was using an Xbox One controller. I'd much rather play with Kb/mouse

Apparently, many encountered this problem and I managed to find its solution quite by accident, just turn off GOG overlay

THIS. It fixed my problem completely. We may should contact GOG directly to let them know about this issue to know if this is a bug related to the Galaxy client.

Already :)

Does this include achievements and game time tracking?

Because I tried just unchecking overlay and I'm still having the issue.

I for my part can confirm that there is no more stuttering going on after disabling the ingame-overlay. I should note as well that I use adaptive V-Sync from the Nvidia control panel, not the ingame option.

In my case i'm using NVIDIA FastSync. I tested the steam version and it worked well. But the gog version needed to disable the overlay.

Well, I wish I could say it's working but it's not. I had to turn my mouse sensitivity down to a point that's almost unacceptable for how I would normally play an FPS. Slightly above how it feels to play with a controller, which again does not give this stutter effect the way the mouse does.

Perhaps we are talking about different problems, but it seems I understood how to help exactly your. :)
1) To make mouse sensitivity more customizable, you can go to: documents -> my games -> bioshock infinite -> xgame -> config - XUserOptions and find these parameters:
MinMouseLookSensitivity
MaxMouseLookSensitivity
And assign them values:
MinMouseLookSensitivity=0.100000
MaxMouseLookSensitivity=0.500000
Then, in the game, adjust the sensitivity of the mouse to your discretion.
2) And if your camera is still trembling, you can go to the control panel -> accessibility center (not sure if this is the case, for I translate directly from the Russian version of Windows :)) -> ease of keyboard work (or something like this) -> turn on input filtering. This should help a bit, but noticeably

Do not perform 2 steps at once. The second step is completely optional and is only the "last salvation."

Just started playing Infinite and I had the same problem, but disabling the overlay fixed it. Thank you!