At the moment I'm looking to upgrade my late 2009 Mac mini's hard drive (with 2,5" WD Blue 640GB). I was looking photos on ifixit on how to do it and get an idea that if I dissassemble mini I can also replace thermal grease too (I have AC's MX3). Usually default thermal greases are silicon based and are not so efficient than MX3. My basic question is if anyone replace thermal grease on mini already? Is it difficult to remove heatsinks from CPU and GPU? What was the temperature drop? Does mini have "push-pull" based pins for mounting heat spreaders?