I'm buying a mac pro and logic 8 soon and I had some questions: 1) I only need 4 cores at this moment, so should I get a refurbished (2x Dual core) mac pro so for a later upgrade I have the two heatsinks to upgrade one or both CPUs? 2) Would any xeox 771 cpu work on the mac pros, could I pair a 65nm and a 45nm? 3) The difference between the ram speed of the current and older generation of mac pros (DDR2-800 vs DDR2-667) makes any "real" difference in the overall speed? 4) Does the mac pro have any technology of reducing Hard drive noise/vibration? (ie rubber suspension) I'll be using all 4 HDs and low noise is very important. I would really appreciate any useful answers, google didn't have any straight answer to my questions.