Installed updated drivers (v5.02) and firmware (v126.96.36.199) on MacPro and Z3100, 24" yesterday. The driver I downloaded on 17th was for the Postscript printer and got the right one last night (18th) after several hide-and-seek with HP. I don't know if it was the doing of HP or something else, but I was a bit disappointed at HP. Actual installations for both driver and firmware was very uneventful and quick. Maybe my installation was easier compare to some since my MacPro is very clean (used only for PSCS, C1, and Firefox, etc. The printer (Z3100) is connected via ethernet. In addition, I have three printers; EP4000 (USB), EP3?? (USB, for DVD print), Dell 1700 (ehternet), and Epson Scanner (FW) connected to MacPro.
I re-calibrate and re-profiled several paper including HP Pro Satin and HP Pro ID Gloss. I cannot tell any differences between before and after so far.
I was very apprehensive about upgrading for many horror stories on this forum but I went ahead anyway. I want people out there to know that all are not that terrible.