The Honeywell 8000 is a good stat. I have one, and love it. I have heard that York/Coleman control boards with hwell 8000 stats have had some communication issues, but only with gas furnaces. I think beenthere is right... you have control wiring issues. The 8000 stat is 3 heat/2 cool, and should handle your system fine. The control board in your heat pump has sensors as well that are part of the decision making process. If you are going straight to second stage and short cycling, as you describe, there is obviously a problem with controls. Your equipment should run quietly at low speed as long as your stat is programmed... including the installer's program... properly and you aren't jacking it around. If the thermostat installers program isn't right, or the wiring isn't right, it's not going to work properly.