Help with car audio system

I'm from the UK, so Buicks arefew and far between. But as far as cars go, often the factory fitted stereos have the option to add a CD changer. You can buy a CD changer > Aux input adapter for some models. It may be worth looking down that route.

 

How about getting a iPod/iPhone adaptor installed?

 

I've used these with auto-reverse players, you just need to ensure that there is no undue resistance in the wheels in the adaptor or the player will think it's the end of a tape and continually switch forward/reverse. I had to remove a smal spring in one to get smooth operation, or try a new adaptor, they are cheap and surprisingly good at passing the audio through your car's radio/casette. Much better than the FM transmitters.