yers, it can be confusing. There are so many G4 models.
The difference is
a) the color of the tower
there is a blue and white or all white which Apple calls Silver.
b) processor speed.
the newest one has a 1gHz or 1.25 dual gHz.
The one release prior has Dual 867 mHz
c) Ports: the newest one has three firewire ports (one is faster than the other two)
And the new one has an optional Bluetooth and optional higher Airport card slot.
The older G4 has only 2 firewire ports and no bluetooth
The new one is named FW 800, then going down the line:
P57 or P58 Mirrored Drive Doors
QuickSilver 2002 EDU Model
QuickSilver 2002
I hope this helps you.