We have a Kawi ninja zx6r 2012.
I put a m4 slip on-on it. Do I need to know anything else in order to not damage the bike since I have not seen any reviews on upgrading 2012 kawis?
I had to remove the ugly muffler and the fat box that the pip connects to, which sat slightly under the bike. Now, a short larger pipe sticks out just a bit from the bottom of the bike and that is where the m4 connects. The m4 ends just behind the foot rest (rider). The bike runs ok and I read about the air causing popping at decceleration like a dirt bike that is not a problem.
It'll be fine. I used to have a piece o' shit GP pipe on my 2008 and it made all kinds of noises.
If you get a Power Commander installed, try to find a MAP for that exhaust and download it to the PC so the engine is optimally tuned. You'll get a little bit more performance, but there's nothing wrong with riding as-is.