Raplacing the radio in your BMW can be done in various ways, but chances are that you would like to add an aftermarket radio while also being able to retain the factory BMW features, look and feel. In most cases, to do this you will need a BMW radio dash kit, some special harnesses to get the job done professionally, and possibly an antenna adapter. The dash kit allows you to pull the old radio out and install a new single din or double din aftermarket radio without leaving any gaps between the radio and trim panel around the radio. The harnesses allow you to connect your existing BMW radio connections to the new radio (varies by brand) without having to cut and splice wires. Last but not least, you may also need a BMW antenna adapter that allows you to plug the existing BMW european style antenna plug into the new radios antenna type of plug. With all of these accessories, you should be able to replace your existing BMW radio with a newer aftermarket radio without too much trouble.