It is a general FACT that you can not go below ambient temps even with water cooling. These sensors are made to be accurate enough to save the cpu from high heat(and they can vary from cpu to cpu as well), but Intel did not design them to be that accurate at lower temps(MB sensors are no better.).
MB sensor shows 17c as the lowest, but the room the system is in was never that cold.
Compressor/phase change/ect can, but those are another story all together.
When you say any luck, are you asking me if RMclock works with my setup? I can give it a try when i get a chance.