Friendly greetings! I like searching for deals but I haven't been able to come up with a substantially better one than US$279 for the GeForce 8800GT upgrade in Apple's own store. It seems rare to find elsewhere I'm on a current-gen Mac Pro, and this upgrade seems to be substantially more expensive than PC 8800GTs. Is there a better place to buy it? I've seen odd sales on eBay with prices about US$75-100 yes, but am uncertain I want to go that route. Also, I have a base Mac Pro config with the Radeon HD 2600 XT: would it be alright to install the 8800GT in the slot above the Radeon, or is that asking for trouble? I've read previous experiences and they seem fine, but any more experiences I can gather and learn from would be fantastic. Thanks so much in advance!