It's not a difficult job to do the conversion - with an RNS-E (EU H unit) from Haaggie and a full Bluetooth kit (M version) from craigyb (both trusted sellers on this forum) I swapped the Symphony II in my new (1 day old at the time) 06 B7 RS4 Avant on Sunday.
From start to finish it took me less than 2 hours - including recoding the RNS-E and instruments, and fitting the microphone into the interior light. (I also did some recoding on the instruments and central convenience module to get them working how I want them at the same time - I have my own HEX-COM+CAN lead from Ross Tech, which I can also use on my wife's 05 Skoda Fabia, and have used to help several local guys avoid an expensive visit to the dealer).
This is the second such install I've done in my Audis (first was an 04 B6 S4 Avant) - all ALL the information I've needed has been found right here.
Unfortunately not (it's my 50th birthday next week and the RS4 is my birthday present to myself) - but I still behave like a young 'un most of the time!
I still like the latest gadgets and "boys toys" - that's why I'm trying to work out how to strip down an Audi phone cradle so that I can hideaway the electronics and just have a "Talk" button on the centre console (if it will work with the H RNS-E and M Bluetooth - the microphone is already wired through the RNS-E to the phone module) - there is no way I was going to give up the RS4 steering wheel!
I will be placing my order for my nav system monday and will be buying the BT unit from NSX shortly there after. I have the MFSW, so if anyone wants to walk me through the tests, I would be happy to try it ... as long as nothing blows up