The stock radio is a standard DIN mount (both the Bose and non-Bose versions use the same head unit), except that the face panel is wider than that of a standard DIN radio. The radio is held in place by a spring clip at the bottom of each side. To free a clip, stick something flat (like a nail file) into one of the slots at the bottom of the radio. Angle the tool so that as you insert it, it travels outward. Once it is in about an inch or two, straighten the tool...you're trying to catch the outside of the spring clip and pull it inward, so that it clears the frame and allows the radio to be pulled forward. The radio will slide forward when both clips are held inward.
There is a connector diagram on the radio. It indicates that there are line-level outputs available in addition to the amplified output.