A4 TDI sport stereo upgrade with Bose speaker system

[AudiJC]

Hi in next few months I am very likely to purchase myself an A4 1.9Tdi sport estate b6 with the the Bose sound system speaker amp etc.

I used to own one of these 5 years ago and the sound system is fantastic.

Basically what I would like to know is how easy is it to install a more modern stereo unit with Bluetooth, usb etc to enable the system to sound just as good. Is it just a case of plug and play or is it more complicated than that?

Thanks in advance 

[BigRed]

I have an A4 Cabriolet- also with the Bose system. I have a CD jammed inside the player.  Did anyone contact you?  Is there someone out there who knows about these systems and how to get at them?