Daystar's newest upgrade kit gives the trayloading iMacs a 400MHz G4 for $100. Not bad, though it's often more popular to get a used G4 tower, they're getting cheaper by the day. Sonnet's HARMONi gives you a 600MHz G3 plus a firewire port (a great mod), but it's $300, far more than any G3 iMac is worth. I seriously considered one of these when they first came out, but they haven't dropped the price in years... I still use my Rev. C iMac for a few things, such as sharing it's printer over the network. It's running Panther and does OK with the stock CPU, but for people interested in stretching the life of their G3 iMac the Daystar upgrade might make sense. Since it's a 7410 chip I'll bet it does not respond very well to overclocking however (not that I'd reccomend that in an iMac anyway). Also it remains to be seen how useful a 400MHz G4 would be running Leopard, especially on the iMac's 66Mhz bus... Anybody out there still using a G3 trayloading iMac day-to-day?