Bro, I too have a 2004 E60 520i Auto Bavaria CBU, mine has the bluetooth too. - its the 2.2cc and by no means sluggish. It all depends how stock the car is - I believe that the CBU units come with 16" rims - and plays a part in keeping the drive smooth,comfortable and responsive. Plus the bonus of reasonable fuel consumption. I get about 600km a tank mix driving.
No plans to sell yet.
Price is as indicated - about 125-145k depending on condition and extras. Interior color choices etc.parking sensors, bluetooth etc. Hassle-free and low maintenance, even the i-drive is the simpler version M-ASK instead of the CCC.