I want to upgrade my 1.8 Dual CPU PowerMac G5. What are some good upgrades? It is completely bone stock. The GPU sucks, it has no Airport card, and an 80GB HDD. So I was thinking new GPU, get an airport card, and put in a 320GB HDD. Otherwise, what else can be done? Is it possible to get a Disk Drive that reads dual layer DVD's? Also, If I get the airport card, do I need to get an antenna?