I have been in touch with DJI support and even have a case number. A little history. Been going back and forth with DJI support for a month. They have been great and very attentive. When I first reported the issue the horizon tilt was pretty extreme. I have done many IMU, Gimbal calibrations and firmware refreshes. It seems to have gotten better after doing an IMU and Gimbal calibration in one spot in my house. All the other locations I tried in the house did not help much if at all. Regardless of how level the surface was.
Anyway the tilt does not happen as often or as extreme. Usually only when flying forward or backward at full speed or yawing quickly. The gimbal corrects itself after stopping but slowly.  The tilt is never more than 0.1 degree or so. I have seen much more tilt in other M3s on YouTube and FB forums. Seems some just do not care. Other's that have extreme tilt issues send theirs back in.
I have heard a few times that all drones will have some horizon tilt in some situations. Is that true? Is 1 or 2 degrees enough to warrant me sending it in? Of course I have seen other videos where there is no tilt or owners saying their M3 has zero tilt issues. Just need some facts on was is expected when it comes to horizon tilt. What falls withing DJI's tolerance specs. Note: I just flew all day at the lake and no noticable tilt. Today I took it up and in some clips I saw a little tilt again. I do not want to risk being given a replacement that might be worse or have other issues when except for the slight once in a while tilt my M3 flys and performs great. Thoughts? Thanks

tilt master here, maybe you can post a clip and we can tell you what we think about it?  having an evo, im very much familiar with horizon tilt lol lol

chances are yours is not that bad and it would be way too risky to get something else that blows.  if you're not having nightmares right now about what you're seeing, it's probably not so bad.

To be very honest, I rarely even notice horizon tilt until I see the video. But even then it does not bother me. I guess I am just not very picky...or able to create video worth watching ;-)