My current setup is a very small and pretty weak 6.5" driver that comes with the mirage omnisat 6.1 speaker setup. The bass sounds good in some part but bottoms out in others. I really would like a sub that never bottoms out, not sure if that exists. The speakers are powered by a denon 2803 and the omnisats are mounted on the celing of a room that is 17x22x10.

Would a pb13-ultra be too much for this room?

It seems that is the sub to get but i am worried about drowning out the music with such a powerful sub.

It is definitely not too much. Nor is any sub. Any sub can be calibrated to play at the proper level to match your other speakers. It will only be overpowering if you turn it up too high. The Ultra would be amazing in that room.