I bought one of these to install in my 2005 Nissan X-trail to replace the stock stereo (CY690), principally because I was fed up of the poor reception of the FM transmitter I bought to play mp3's from my Sandisk E280 mp3 player. I figured, why not get bluetooth capability as well as the ability to plug in the mp3 player directly via a 3.5mm jack. But what I also wanted was to retain the functionality of the stock steering wheel audio control stalk and the voiceover audio from the built-in satnav.
Am not disappointed. The order turned up the next day from Dynamic Sound Ltd. It comes with facia, 3.5mm jack lead (which is not very good quality), a set of leads that convert from ISO to the Sony specific input socket. I had to buy an expensive (nearly half the price of the stereo) ICT 29-644 converter lead and Sony Remote Adaptor (ICT 29-008) from http://www.caraudiodirect.co.uk to interface with the Nissan specific connectors (they also do other manufacturer adaptor cables as well). It worked first time (just make sure you also plug the aerial in otherwise the BT2600 will just sit there and do nothing) AND I have full control from the steering wheel AND the satnav voice-over mutes the audio when it's talking.
The sound quality of audio play back is very good, much better than the stock Nissan stereo. Linking my phone in was childs play (once I'd read the manual). I have a Motorola Razr v3i which has excellent voice recognition, so you can voice dial at the push of a button. The BT2600 mutes the audio, you make your call, and when you hang up it unmutes the audio. Superb! I have yet to try making a call whilst driving, so I'll edit this once I've done it (so I can confirm whether the sound quality is any good).
I have also yet to try the CD and mp3 from CD functionality, but since I have an mp3 player anyway, I'm not too fussed about it.
I was sceptical about the adaptor cables retaining the satnav voiceover (which I don't use anyway), but much to my surprise, it works! The satnav voiceover comes out of the front passenger side speaker and the music audio is partially muted, which is exactly the same effect as with the stock Nissan stereo. Bonus!
So all in all, I'm very very happy with it.