I've just bought a new head unit for my car, a Sony MEX-BT2600 which features A2DP Bluetooth as well as a full Hands Free Profile (HFP).

I've had some positive first hand reviews about this and it will suit my needs down to the ground as I do a lot of driving for business and get fed up of lugging lots of CD's around with me. With this HU, I'll be able to stream my entire music collection off my N95 as well as use the in car hifi as my hands free system and give up wearing my annoying little Jabra earpiece.
The unit will hopefully arrive this week, but I was wondering if anybody else had experience of this (or it's predecessor, the BT2500), especially if they use their N95 for TomTom navigation. I'm wondering how things will fare if I am running TomTom (phone connected via BT to GPS receiver) with the Music Player in the background and also for phone calls. Can the BT protocol handle all that at once or should I expect to sacrifice performance of functionality ?