I recently noticed that one of the rear speakers in my daughter's '96 328is sounds like it needs replacing. Any suggestions on what type of speaker to use? I know it's not easy to buy single speakers. Also, the Business CD radio has very poor AM reception. I'm thinking that the antenna may be disconnected or there may be some other issue. Any ideas? This car is not old enough to have an external antenna rod like my '93 Mercedes so I'm thinking it must be embedded somewhere. I don't see anything in the windshield like there is in some older cars. Thanks!