Myhre ,
I get down to the negative teens/twenties when I am at idle. Are you still using the spring loaded screws on the mounting head for the Prometia? Have you had a problem before not making full contact with the heat spreader? Last question, did you maybe use too much of the seal string? Have you still running your corsair at 1:1 with the timings in your sig?? If so, those are some very impressive sticks of PC3200, but it makes me think that maybe that may be holding you back. If you have not tried yet, you should try a different memory ratio just to rule that out.
I am also considering trying to get mine re-gassed. But figure that even only being in single digit +/- temps under load is better then nothing. Another side benefit of having the prometia is that it seems to be cooling the PCB of the motherboard around the entire area of the CPU and the power regulators/mosfets. This helps on keeping the board temps down as well.