I agree with Mort on everything.
But let me add... Just my personal opinion, FWIW, I would not want to buy a G5 PowerMac without some type of warranty. In my experience, expensive parts fail on the G5s more often than the G4s. If the 2.0 either has Applecare (which can be transferred to a new owner) or is still under warranty and eligible to add Applecare, then great, go for it.
Otherwise, I would would pass on a non-warranty-covered G5.