First I would like to say hello, I'm a new AVIC 411 member. I just purchased a refurbished AVIC Z1. The manufacturer date on it is March 06, I was wondering, can I do the Bluetooth update on it or not? I would like to do the update and the 2 wire mod, but I'm not sure if I can do it on the March 06 unit.

Yes you can. The update may be done already depending on how long ago it was refurbished

If you already have the Bluetooth update, then when you insert the cd containing the update, it will just say you have the latest version already. So no harm done.