I replaced my stock radio with an Alpine IWA-900 a few weeks ago. The install was pretty easy. I used a Metra dash kit and wire harness. I also ordered the PTR7 bypass module for the e-brake/foot brake sequence. I don't watch dvds while I drive, but to access other settings and some nav features the car needs to be "parked".
I just removed the bezel around the radio. I didn't have to remove panels from the glove box to make my way over. Install was pretty easy other than cramming all the wires and BT module behind the dash.
The sound has greatly improved, but the speakers need to be replaced. I'll probably swap them with some Kicker QS components later on. I don't plan on doing a subwoofer or amplifier. I may do the mini alpine amp that does 45w per channel and fits behind the dash.
Here are some pics.
BT microphone placement:
The mic placement was tough. I put it at the top of the pillar and roof liner, but there was too much road noise and feedback from the speaker. I tried ontop of the steering column, which was better but still not perfect. I kept my g/f on the phone for about 30 minutes playing with placement until she could not longer hear ambient noise or echo.
The navi interface is fine for me. I rarely will use it. My g/f has an Acura TL with navi and the interface and graphics are very similar. Overall I really like the unit and would recommend it.