I currently have a PowerMac G5, and I'm going to buy a new mac pro soon. I just was wondering what I can get low features on to save money. Obviously I know the ram and video card and HDD, but can the processor be upgraded also? And can the video card be replaced with a PC card? Or is that still like the IBM days where I'd have to pay over twice the amount for a card that the PC has had for a couple years?