This Limited-badged Taurus caught hot weather testing in the South West is pretty easy to spot as a SHO. The SHO-specific wheels are the dead giveaway, but out back we also see the SHO's two large tailpipes poking out of a modified rear valence. What's particularly interesting is the car's front end, which is heavily wrapped, most likely to obscure design changes to the 2012 SHO's front end that will further separate its look from standard Taurus models.
While we there's no evidence in these spy shots confirming that Ford is pushing the car's 3.5-liter EcoBoost V6 up to 400 horsepower, the fact this car was caught hot weather testing could indicate that engineers are there to see how a more powerful version of this engine acts when the mercury skyrockets. That said, they could also just be testing how any changes to the front end design affect engine cooling for the current engine.
We're also hoping they're testing new brakes for the SHO, because the current car's stoppers have enough trouble hauling down this heavy sleeper sedan without another 35 hp making matters worse.