[Andysdad]

We recently purchased a 2005 Prius with Package 1 and some dealer added upgrades. Is it possible to upgrade to a package 4 or package 5?

Thank You

 

[DanMan32]

It is extremely impractical to add HID, VSC, side airbags, NAV or JBL.
You could add the homelink dimming mirror, or an external CD changer, that's about it.

 

[ehurtley]

Unfortunately, the vast majority of the difference between packages is something that can only be changed at manufacturing. As Dan said, you can add the mirror, and a CD changer, but you can't 'upgrade' the whole radio to the CD+Tape JBL over the CD-only. And the more drive-oriented technical components are absolutely out of the question. Your best bet would be to sell your current car (if you're in an area with long waiting lists, you could even concievably get more than you paid for it; although some would call that unethical,) and get the package you really want.