Hi everyone. I am thinking of upgrading the processors in my 2006 Mac Pro (2x 3Ghz dual core 5160). So, I have two questions. Is the Intel Xeon X5470 A viable replacement option? If it is, is it ok to go the used processor route? I'm looking at a pair of used ones from this site: http://www.itcreations.com/view_product.asp?product_id=22752&pn=PAIR+SLBBF+&s=gb Will those work I my 2006 2x Xeon 5160 Mac Pro? If so, how does the site I listed look, and are the used processors a good idea?