I have a 04 S2k and I am wondering how to take off the stock radio because I am putting a aftermarket one. And is there something I can buy so the audio controls can still work. Thanks

 

You're going to have to pop the cover off from around the radio with a flathead screwdriver. It goes from about 2 inches above the radio door all the way around to right below the vent. Then there are screws on each side of the radio if i remember right. Take them out then pop the wiring harnesses off. Installing the new radio is pretty self explanatory too consult the Audio section. Here is the adapter to make the dash controls work http://www.modifry.com/products/dci/wired_dci.htm

 

there's a FAQ stickied at the top of the forum.
in addition, this thread may be useful.