You can drop in a dual 1Ghz CPU (The fastest stock speed available) and max out the RAM to 1.5GB, for around $125 if you want to go a step further, you can buy a used ATI Radeon (Eg. 9600 XT) and flash it to run on a mac for about $25, if you have no plans to connect an ADC-Based Apple display. You will however need a PC to do this. If you need help flashing a card, let me know, I did one this week, and have all the info with me.