Swapping factory installed stereos

I would like to swap the basic AM/FM stereo in my 1999 Chevrolet Astro with the better stereo/cd player in my 2000 Oldsmobile Silhouette. Does anyone know if this can be done without modifications to the Astro.

The wiring harnesses should be the same and plug right in with no problem. However the way it mounts into the dash will most likely be different. It may slip right into place depending on how much bigger or smaller the radios are from each other but the mounting brackets will most likely be different.