1. No idea, other members should know.

2. Press MENU and then go into Settings. Tell me what version number of the nav software you have in the upper right corner of the screen.

There are two things at work here. One is the navigation software, which you can update with disk images you can download here. If you have the older versions, the resolution is crappy and the newer one gives you a much clearer pictures plus nice views like perspective.

For your house not being on the map, and the fact that you are living in a recent development - tells me that you have an outdated navigation disk. Eject the one from your navigation drive (in the trunk open the left compartment and press the eject button on a little black box) and tell me what date is listed on the DVD. The latest navigation DVD is 2007-2 and can be purchased from your BMW dealer (or if your crafty can be downloaded from the internet and burned yourself).

3. 4.8is should have DSP, which was previously BMW's highest quality sound system (newer cars have logic-7 systems which I hear are phenomenal versus OK for the DSP systems). You should find many articles here on members upgrading the DSP system. However I will warn you that its simply not a swap the old speakers out/swap new speakers in kind of do-it-yourself. You'll have to deal with the DSP amp, and BMW's strange speaker sizes. Other members have done it and can help you out here.

4 & 5. Go for it.

6, 7 & 8. Others can help you with.

9. It is illegal in the U.S. to have a system that plays DVD's in-front of the rear seats. Therefore BMW disables the TV/Video function on U.S. bound cars with navigation systems. Therefore, the functionality is there, however it is locked at present. There are tools out and people out there (nav-tv I think is the name of one) that can help you unlock the functionality.

Hope these answers help. I can't help so much with the engine things, but if you have more nav questions i'd be happy to help...