[qtrracer]

My 86 GT also had the premium sound system. The outside holes are for the 3.5" speakers; the middle hole is for the premium amp. To get to the speakers/amp, you need to remove the dash pad. There are a bunch of screws accross the front near the window, I believe three up under the edge of the gauge panel and about the same number above the glove box panel. Once those are out, take every precaution removing that pad - mine was so brittle it cracked and the repop replacements are less than satisfactory. NOS or prime used pads fetch premium money.