I came out of the CK exam not knowing what hit me. It was fairly tough, had to mark between 6-10 questions per block as unsure. I checked answers after the test and so far confirmed I answered in total 4-5 questions incorrectly already. 4-5 may seem little but I decided not to check anymore as I think I'll get depressed further haha.

I'm hoping for a good score, but as a non-US citizen IMG looking to apply to an IM residency in an academic medical center what is considered a good/safe score?

I did well in step 1 (262), passed step 2 CS and have had nearly 5 months of US clinical experiences, presented research in multiple US conferences and published 7 papers and a book chapter. If I do less than well on CK, say below the good/safe score, how will it affect my chances?

It looks like you have solid work and a very good chance of matching in the academic center of your choice.
I wouldn't worry that much about how you felt leaving the exam, it is a common feeling among test takers (I had it too with Step 1 and got a good score). How you feel rarely reflects how you scored.
Could you please help those of us who are still preparing for the exam with some advice on the prep?
(like:What were your resources? How much did you prepare? What were your NBME scores?)

Good luck!

don't worry about it. you will be fine. just make sure you apply to many different programs.
262 is a stellar score. you'll be okay. don't worry.