Are there any cd changers that will actually work on a 99 A4 ? Or do I have to buy the one at the dealership ?

many manufacturers (alpine, nakamichi, pioneer) make cd changer that work via FM, no mods necessary on your current setup. Depending on which kind of head unit u have, you could buy an alpine changer and take a pre-out from your current unit as an aux in to the alpine, and make that your primary control piece

and I bet it's much cheaper than what your dealer will sell it to you, unless ofcourse, your dealer is Clair. For a 99 you need to get the mounting bracket too, 99.5s and up you only need 4 screws.

Other options are to buy it from Autotoys.com, it's cheaper, by $40 I think, but many have complained of their poor customer service. There are other places that sell the unit, can't really remember who, I think one of them is Rockville (?) Audi, a dealership in MD, not sure, you'd have to search the archives.

You can install it yourself, there's a FAQ written on this.

HTH,
Mark K
99.5 1.8T qms

Talked to Clair. Be aware that since they are an Audi dealer, the warranty is as good as if you ordered your car with the changer installed. That is the information they volunteered.