"1-2* C better cooling than the best WB out there..."
This project shows how well direct die cooling can perform:
http://www.upload.cooling-store.de/Fluidus/V1/start.htm
The best temperature difference he could reach with a commercial waterblock was 26,7°C, the best direct die cooler reached 5,7°C.
To avoid the other problems Phant0m51 mentioned i currently try this one:
http://www.wakuebau.de/index.php3?up...9&lower_cat=21
The hole in the bottom is a bit smaller than a T-Bred B die.
I applied the cooler with Silvergrease, the leak test ran for 7 days now and i didn't recognize any problems.