Is there a list anywhere on the site of drives the work and drives that dont, or do I have to go through a million posts ? I did a search, but did come up with anything.

Just about anything made by Toshiba will work. If you have the dough, you could try out a Solid State Drive too.

Whats the most cost effective way to unlock the oem hard drive, I see the post for the one that cost $40, but I thought I saw another saying it can be done for $5

It depends on what you want. If you want to keep songs from your oem drive that you've ripped up until this point, you'll want to go with the more expensive option, as it won't destroy your data.

However, if you don't care about the data on your drive and just want to upgrade to a clean Z3 image, the 5 dollar option would be fine.

Sweet thanks, I just found the post for http://www.hddunlock.com/ $5 unlocker.

One more question, I have another drive I might try first, do I have to unlock that first as well.

You don't need to "unlock" a drive if it's never been inserted into an AVIC unit, however you DO need to "disable" the security so when you do insert it into your headunit, it won't lock.

Do a forums search for MHDD and it should give you all the info you need for that.