How much was the dsp kit? I didn't order the dsp kit, I bought an analog to digital converter off of amazon for $40 bucks and it had the RCA connectors on one end, and the coax on the other end. I would assume that bmw has a coax that would work as the older cd changers required it. I would look at real oem, like 97-99 5 series to see if you can find that coax, or send the dsp kit back and get a converter like I did.