I have to replace my HD in my Pismo and I can't get a definitive answer. The specs say I have (OEM HD) an Ultra ATA-66 which when I search for a replacement, nothing like that exists. I have a Toshiba 40GB 5400rpm in it now (a replacement) which is an ATA-5. I have posted to other forums and others recommend an ATA-6 but I was under the impression that won't work. xlr8yourmac is not definitive as the posts there say they have G3 500's or G4's so my question is: Will an ATA-6 work in my OEM Pismo?

Pismo G3 400 1GB 40GB Toshiba MK4019GAX (dying)