Man, I don't know, good question. I looked for some HU picks online in an e30, but couldn't find any that confirmed one way or the other. Have any pics.
Does your head unit have two little flaps on either side of the radio, half way down each side? If so, I don't see why not, you would then need to determine whether the wiring harness' are the same. Pics of your deck and wiring harness would help greatly.