well when you research the engine ford upgraded the engine a lot to stand the supercharger like rings, rods, and heads to cool the engine better so it is harder to blow the head gaskets. the only real way to blow the head gaskets is to have the water pump go out or stuck close thermostat and have the engine over heat is really the only way.
Have you read on the Super Coupe forums about the reliablility of those motors? Despite the better internals the SC 3.8s got, they still have issues with head gaskets. A Chevy 2.8 head stud kit helps but either way expect to deal with that.
Also the 3.8 in those is set up to fit a M5R2 trans or AOD, either of which will take some work to fit in your "Expolorer". Engine mounts and exhaust will take some work as well, and piping and mounting for the intercooler. Then you get to wire it all up, though considering you'll pretty much need a whole T-Bird SC (~$2500) that won't be too much of a nightmare. But still, don't expect to find lots of topics on the web detailing how to install a 3.8 into a Ranger/X.
When you finally have it together, you'd have a motor putting out around 210/315 for hp/tq. And aside from cranking up the boost (goodbye head gasket) you'd be about stuck there.
Or, you could start out with a 4.0 SOHC (210/255) which would pretty much drop in without mods and go from there. You could even supercharge it, as there are kits available. Or, you could install a 5.0 (225/300 in the 87 Mustang) and go nuts with all the aftermarket support. You could build it to any power level you wanted, N/A or forced induction. The install wouldn't be that hard, as it's been done plenty of times, with numerous online writeups.
I guess what I want to know is if you are serious and skilled enough to do the motor swap, or just fantasizing. Being unique is one thing but if you can't finish the project, it's pointless. And the 3.8 is not necessarily the most bang for your buck.