This 2001 Ford Mustang RP6 is a rare prototype of a limited edition model known as the 380R, a supercharged GT offered by one of the more recognized Mustang builders and tuners. The example shown here is believed to be one of six prototype “RP6” models that featured the full assortment of performance enhancements as sort of a rolling testbed before selling the Roush-tuned muscle car to the masses. The seller has listed this rare ‘Stang here on craigslist in Alabama with an asking price of $25,000. Thanks to Barn Finds reader Adam C. for the find. 

The world of aftermarket-enhanced Mustangs is quite vast, and collectors really do have their choice when it comes to picking up a limited edition model. The name Roush is right up with there with Saleen and Kenny Bell, and I’m honestly not sure how you decide which one is the “best.” Certainly, Roush has spent many years learning how to uncork the most performance possible out of a Mustang across multiple generations, and given the platform we’re looking at here is one of the lesser loved ones, the supercharged powerplant does much to transform apathy into interest. Despite being a “test mule”, there’s a healthy 69,700 miles on the clock.

The interior is surprisingly low-rent, although perhaps not for a test mule car. The cloth buckets are nothing to write home about, and that’s perhaps the most disappointing feature given production-ready Roush models typically have thickly-bolstered sport seats inside. The Mustang is also equipped with an automatic transmission, which is responsible for harnessing 380 b.h.p. Speaking of the transmission, a previous auction listing here on the Mecum Auctions website seems to show the same car, and if it is, the listing there describes it as a test model for the 4R75W auto transmission that would appear in later models.

The Mustang is signed by the founder of Roush Performance, Jack Roush. I’m not sure it carries the same weight as Carroll Shelby, but it’s still a nice bonus. The seller claims he has owned the car for ten years and the chain of ownership doesn’t jive with the listing description of having had it in his care for ten years, so the Mecum car may not be the same one. Plus, this one wears Cobra wheels, which I like better than the torque-thrust style seen on the Mecum model. Overall, I’m not sure how much value is added for this being a Roush prototype of a Mustang generation that was far from the most loved – what do you think a Roush prototype should be worth?