They both fit. The wiring connections are the same between the two. If you plan to run the factory CD changer, the Pioneer radio will only communicate with a Pioneer changer, and Alpine radio will only communicate with an Apline changer. Course everyone uses iPods anyway, but just a heads up. __________________ SOLD!!! 1999 332ti //M Sport Titanium Silver M3 S52 3.2 I-6 Engine, M3 Clutch w/ ti Getrag Trans, Z3 3.15 LSD medium case diff and half shafts, OEM Hatch Spoiler, Eurosport HP Underdrive Pulleys, FDM, 17" DS1 rims, M3 Front Struts & Springs, M3 Instrument Cluster, 3-spoke //M steering wheel with tri-color stitching, SSK, CCFL Angels in Depo projectors with 5k HIDs |