It would be helpful if you actually explained what you already did. You said you remapped it. What exhaust/intake mods are you running?
I have my doubts about that Ninja intake cams story. A Versys with two intake cams (Ninja or Versys sourced) wouldn't run at all, let alone better. Maybe they switched to Ninja cams (both intake and exhaust), which would make more sense and has been done before. The thing is that after all that work, the gains are minor. In order to get the gains you read about (like those that are used by those racing Ninja 650s) a lot of work is needed.
Here are some parts, shipping may be free if you buy enough, but installation is not included:https://www.spearsenterprises.com/product-category/kawasaki-er-ex650/
There is a good reason for the joke that asks - How do you make a small fortune?
You start with a big one and go racing...
If I didn't have personal experience with that, I would have thought it was funny too...