Yes escos and 4x4 saphs use pretty much all the same running gear, the escort cos basically has a saph floor pan so everything underneath is the same.

However by the time you have bought a escort cossy shell, and a 4x4 saph, you probably would of spent as much as it would cost to buy an escos complete, unless your getting the escos shell for under 3k.. (in which case it is most likely a tracked out car/and or on a duff ID) Alot of the escos shells about at the mo seem to be motorsport versions on rs2000 id's and stuff. ..