some functions work, some don't, but don't forget what you pay in europe for these working functions:)
I got mine z2 refurbished in US (legal, not stolen! - hate stolen stuff) for ~600EUR with shipping to NY. European equivalent (used, origin unclear) is ~twice more on ebay.
WHAT WORKS:
I drive in Central Europe (Czech Republic, Poland, Lithuania, Germany, Austria), I use it for CD/MP3 playback (works fine, good sound quality, advanced sound settings - I have an amplifier), rear view camera (works - very important for me, saves space and very convenient), music from harddisk (works, and I will fix the ATA protection "when I have time", so it will work even better with more mp3:), and radio (works, but not TA or AF), and DVD (works, because most people to not use originals - make a copy of your region 2 DVD through Shrink DVD and keep your kids happy in the car).
PROBLEMS:
GPS does not work, so does radio TA (quite bad, because I got used to it from before). Needless to say, makes no sense to try watching anything but original region 1 DVDs. Note to European readers of this message - please check the number of films available on region 1 DVDs and the prices - if you are into quality films, you will end up having a lot of originals from region 1.
I did not even bother connecting the GPS antenna, because I know all the US gps functions and maps are useless. However, the GPS device must use maps from certain companies, tomtom, garmin or other. It is a PC, very simple and stupid, but a PC. If I really have to fix the GPS (at this point I have done to much driving in the cities I go to to rely on GPS 'navigation' - I have my own shortcuts), I am sure I can google out some smart guy on the web who has some solution to it.
INSTALLATION...
... is easy. Cables are labelled/marked in the packaging (interesting to note, the unit is made in Chine, but cables are 'Made in Japan'), so just look at the installation manual, and do it.
Here are some comments (these may be against Brussels designed safety regulations, so think about using them:) - take the risk in EU!
1 - connect ground, +12V permanent and +12V ACC cables to begin with.
2 - connect your amplifier or speaker cables (sort out cinches/channels and colors of the wires; requires diligence, but easy)
3 - think whether you want to connect the driving lights input; if you drive with lights on all day and year, the dimmed display will be difficult to see on a sunny day. On the other hand, the display is quite bright on the night of December 24th - think about installing a little switch to control the input from lights, if you are bothered by display brightness.
4 - speed control and hand brake inputs - just test their role in your car. The first one is apparantly related to navigation (when you are in a tunnel, the navigator calculates your position). I did not connect it. The second one decides which functions work when the the car is parked/moving. My idea was to have all the functions working regardless whether I am driving or not. So I am driving with the handbrake 'on' all the time:)
CONCLUSION
Think about what you expect from your car stereo for the money that the american unit costs. When I checked the cost pioneer/jvc units with similar functions in EU, the results I found are more expensive (you may be luckier - please check the price yourself) than the north american avic z2. So I think it was worth it. Even if GPS does not work, and it does not have TA function. I like quality sound, and hate cables and ipod connectors and chargers (even with rockbox). Avic Z2 does the job. And also gives hope that "some day" I will load the EU maps.