I use one of these heads on a Gtizo systematic tripod - no panoramic base (directly mounted to the tripod). The stabiliy is simply as good as it gets (at any cost). I frequently use a Linhof 4x5in camera with a 500mm lens on this setup, and it's so stable, I can rap the front of the lens with absolutely no visible movement in the image whatsoever. Rock-solid metal-to-metal contact.
If you need more stability than what you currently have (whatever it is that you have) get one of these heads on a big Gitzo. Nothing else comes close!
Good luck with the sale! (no connection to seller)