Large drive support
The first tower G4 that has "large drive support" (meaning larger than 128 gigabytes when plugged directly into the logic board's ATA bus) is the Quicksilver 2002. If you want a larger drive in a Mac model earlier than this, you can use either a PATA or SATA PCI slot controller card, with a corresponding drive plugged into it. The advantage of SATA is that the drives have become cheaper than PATA, especially the larger you get. SATA is only somewhat faster than a good fast PATA drive, at least with this configuration, unless you install a 10,000 RPM SATA, which is a speed not available for PATA drives. The largest 10,000 RPM SATA drives are 150 gig, but you could make one of these drives your startup drive, and connect a larger, 7200 RPM SATA drive to the controller card for more storage.