I've been reading the threads trying to confirm what I need to upgrade to bluetooth and what features I'll lose by the switch. My local BMW dealer is has been telling me that upgrading to bluetooth for the 2004s is nearly impossible and too costly. But the threads conflict with that info.

My Details:
2004 X5 with NAV and DSP - Production date 10/2003

It seems that the recommended solution is to use a BMW Bluetooth retrofit Kit. Such as one from bimmernav.com.

It seems to have the latest ULF:
84 10 6 980 130 10th Generation Bluetooth ULF from BMW

I guess I have 3 questions:
1) It seems that during the install I will be disabling BMW Assist module. Is this correct? Not a big deal to me just trying to confirm.
2) Will this upgrade support voice reg for bluetooth and Nav system?
3) Since the 2004 models have BMW assist and therefore a microphone is there any need to upgrade to the latest microphone model?

Thanks