I haven't heard of a specific kit for fox-bodies but the TRUCKS! show on SPIKE TV did an episode where they installed and tuned a non-specific STS Turbo kit on a first generation Lightning. Might be worth checking out on iTunes.
if you go to a y pipe config on your exhaust it would be simple, but there is plenty of room under the hood for a turbo so I dont see why going sts would really be something to consider