I'd be interested in any replies to this one too. I still have the original radio/CD player in my 04. CD player no longer works, but since it is just my daily driver to work, I haven't given a replacement much thought.
With a $400 budget, I was looking for a unit that would give me FM/Bluetooth/GPS. I learned that Garmin isn't making GPS/maps for car audio decks (in my price range) and some unknown company is making the maps, which can *not* be updated. Without being able to update the maps, the GPS is useless. So I went to plan B.
I bought a Pioneer MVH-X580BS digital media receiver with advanced Bluetooth for $100 from Crutchfield. This receiver has been rated the best in it's class, and Crutchfield included the wiring harness, plate, instructions for my PT Cruiser, and free shipping for $0. I also like that Crutchfield has free tech support for the installation. This Pioneer deck is fully integrated with iPhones; calls are 100% hands free, and you can play any music from your iPhone without plugging it into the deck.
For the speakers, I bought Kenwood KFC-P709PS for the front (two 6 3/4" plus two tweeters) for $100. For the back, I bought Rockford Fosgate Punch P1683 ( two 6" x 8") for $80. I also bought these from Crutchfield (again they included all the wiring and installation pieces free). In my speakers I was seeking quality (no paper) that didn't require an amplifier. I like to listen to classic rock (loud) and talk radio.
The only other pieces I bought for the installation was Posi-Products Car Stereo Wiring Harness Connectors for $5 (they make it easy), and Bojo Trim Panel Tools (3 tools for $12) so that we can get the panels off easily without marking them.
So for $327, I will have real audio and full technical support by phone for the install.
My Plan B includes buying a separate GPS unit (Garmin with lifetime free maps) and the Garmin wireless backup camera that is viewable on the GPS screen. In owning my 01 PT Cruiser for a week, I've learned that it's not easy to see out the back. I haven't bought these yet. It's $100 for the backup camera and about $130 for the Garmin GPS unit.
Once we install it this weekend, I'll post an update about the experience.