My new dream car- BMW 328i convertible

I just bought this nice 2008 BMW 328i convertible car... off course it has all the options included a NAV- GPS, in which I will be installing a DVD player and Digital TV to be integrated in the dashboard screen and controlled by the iDrive button and strering wheel buttons. I found 2 companies that sales the Multimedia interface to adapt the NAV to other video inputs like video in, rear view camera, SD card, etc Does anyone recomend any website for me to look for a good Multimedia interface , DVD player and TV? I love this car. I hope to keep this car for 4 or 5 years...