I'm considering adding a navigation system to my current car (BMW 5 series) and have been looking at the Alpine 1-Din system. There are a couple of things that I'm wondering about: 1. How feasible would it be to retain the original BMW head unit and refit this when I come to sell the vehicle? When installing the unit I guess they'll have to use a fascia adaptor as the standard head unit is a unique fit jobby. 2. Can I keep the existing BMW autochanger and refit this if the car is sold? 3. Is it possible to get any of Alpine's DVD stuff multi-region, or even R1 rather than R2? 99% of my films are R1 so R2 is really not that appealing to me. I may wish to add a DVD/CD changer in the future. 4. The current unit only has a single tuner so to receive TMC broadcasts you have to be permanently tuned to Classic FM. There is an add-on unit (which is anywhere from £229 to £250) that allows you to make "full" use of TMC. In a nutshell, it's another tuner that can stay locked to Classic FM. Rather than purchase this, could I get an Alpine DAB tuner instead and use this to stay locked onto Classic?