I have recently changed my standard head Unit for a JVC KD-AVX33. This comes with Bluetooth as standard, DVD, AV inputs and can take GPS (with an additional module) as well as your Ipod (with a module also). I looked at various Becker Head Units, but ruled them out on the grounds of cost and because they seemed rather paltry in comparison with the JVC. My unit has the ipod module, which also does away with the need for a CD changer.The setup cost me £350 on the web (including the ipod module), and £50 to instal. It looks good and sounds great
I have the same unit in a new beetle, but that one is hooked up to a Digital tuner , a roof-mounted flipdown monitor iand a cd changer in the boot. Based on my SLK experience, the boot CD changer is to be given the BOOT and replaced by an ipod module.
The dash-mounted flip out monitors will inevitably obtruct your controls, and are also a thief magnet. I have looked at a number of them and find that they are over priced and thin on features.
Have fun with whatever you decide!
Lastly, I'm a SLK newbie, with a 1999 SLK230; black with black leather interior.