does the 93 already have power windows? if it does, should just be plug and play...
if not, just snag the harnesses out of the 89's door that go to the window motor, and if memory serves correctly, i *think* that all the later model stangs had the same dash harness so you could put power accessories into a non-power car...
i know we put power lumbar seats into my friends 91lx that didn't originally come with them, but the connectors were right there under the carpet waiting to be utilized.
if you look under your dash above the kick panel and see a couple of 8-pin connectors with pink wires just dangling there or tucked away behind the insulation not connected to anything, those are for power windows, and locks...
The 93 doesn't have any of the wiring that is not being used. The 89 main harness is labeled 14A200 and travels from left to right under the dash to the kick panel. The 93 is a non power window car. So until I can tear apart the left side It looks like the entire dash has to come out.