Pepper K496,
That's the beauty of the STS Turbo system....you don't need an intercooler. The long piping from the turbo to the intake and the turbo location (by the rear axle) eliminates the need for an intercooler.
Depending on if you want a single or dual turbo system, piping should under the Sport Trac should be a snap since there is a ton of room under there. The only real tight place is around the spare tire and gas tank. And if they can put 2 turbos under a tightly packed chassis of a Corvette, the Sport Trac should be a piece of cake.
My only question is, does STS sell a kit for the Sport Trac? It sounds like the shop you went to are going to custom fabricate the pipes to fit your Sport Trac, and of course, that will cost a lot more than a true bolt on kit.
...Rich