If youre looking to do a 16:9 with a cd slot behind it then youre going to have to swap out the c43 radio tuner in the trunk. You can plug the 16:9 unit in with the c43 but it will still "think" its a cassette player and the monitor will open and close continuously. You would have to upgrade the radio tuner from a c43 to a BM53 tuner. In addition you will need a retrofit adapter that will convert the plug for the c43 into a plug for a BM53 as the two units use a round connector and a square connector. You can purchase this adapter from European Auto Source for $125.

I tried doing this in my E46 and it didnt work. The monitor wouldnt stop opening and closing. Also the cd just kept ejecting.

I hope this makes sense. Others tend to get confused as there is very little info on the different radio tuners out there.