OK, the N900 is the best device, but the BT really sucks:

1) A2DP profile with my car device Bluetouch.de doesn't work at all. No problems with N95 and iphone. I sent the problem to the manufacturar (bluetouch crashes, regarding the logfiles), but for me seems strange that many device work out of the box.

2) making calls (HSP, HFP profiles) with Bluetouch in the car. Basically works, but sometimes doesn't accept the call or I cannot make calls.Completely instable. No problems with the above mentioned devices.

3) using N900 as modem on the XP Laptop. Comes up with an error.
I will check the APN, I'm not sure here, if this was configured well. I used the same settings as with the N95.
Filetransfer worked well, that was the only highlight so far on Bluetooth.

Hoping problems been solved with PR1.2.

If you read Changelog PR1.2 you see that BT carkit bugs not resolved

Indeed - they are not resolved in LPR1.2...

For A2DP you can try forcing (using DBUS) the phone to connect to the stereo - I had a thread on here showing how to do it. It works for my Ford Sony.