Hmm... after mulling it over (and getting the idea from this guy), we're starting to think this prototype may actually be wearing upgrades destined for a high-performance version of the Sport Trac that would be based on the Sport Trac Aderenaline Concept from 2005. Think about it: relocated twin tailpipes out the back, a lowered front bumper (chin spoiler?), same headlights but a new grille that looks lifted straight from the concept. The covering could be hiding a new hood or the concept's giant fender vents behind the front wheels, and that tape applied around the rear well could suggest larger fender flares for a fatter wheel/tire combo. Sure the wheels and suspension on this prototype are standard Sport Trac fare, but that doesn't mean this mule couldn't be testing cooling or other components of a high-performance model. Whatever's left of SVT, this Explorer Sport Trac prototype could possibly be the fruit of its labor.
[Source: Winding Road]