xafier: I have no clue what you glued and made there, sorry.
About the Gigabyte X38 DS4, you should turn Ninja PLUS by 90°, because on one side of the cooler the heatpipes are sticking out more than the other. The heat is not the problem here
As for the Push Pins, they have a lot of pressure but if you are not lucky with them or do not put them tight enough inside, might be not that good. Overall they are ok to be used, you can even mount 2kg with Push Pins, it's just a fact that it works out, unless you do crazy things...
Thermal grease gives you maybe 1-2°C based on what I remember, if you use the liquit metal, I don't calculated that in. For the difference between A64 and E8200, these are 2 different types of CPU, forget about the comparison, because the A64 did not use the same way of measuring the temperature to start with.