I have one of those in #18. I got it out of a 88 turbocoupe awhile ago. Never installed it, I think it is sitting in either the 86 svo or 85 turbocoupe.
Found the equalizer, though one of the little black tabs isn't over the green rectangle on the slider. Still looking for the radio, found the regular stock radio (not the premium one).
Let me know if you find the radio that goes with the EQ. I am in Georgia. My e-mail is bdmiller538@aol.com. If you find it decide what you want for it and let me know.