I need a radio i might get a factory one but i've been seeing some nice alpine radios. My question is if i want a radio that isn't the factory radio how do I know if it will work with my car which is an e36? Also the only radios i've seen aside from the factory radio is alpine and sony are there any other companies that sell radios compatible with my car and if so can anybody give me any links to sites? Lastly i'd like for the radio to work with my 6 cd changer.