Barely Driven 810-HP Ford Mustang RTR Spec 3 Is Up For GrabsGuessing HeadlightsAndre NalinFri, September 11, 2026 at 10:00 PM UTCAdd us on GoogleImage Credit: Cars & Bids.The current Ford Mustang GT already offers plenty of performance straight from the factory, but RTR is happy to turn the wick up considerably. Add a supercharger, upgraded suspension, and some distinctive styling, and the result is a muscle car capable of embarrassing considerably more exotic machinery.One such Mustang is already looking for its next owner despite barely having time to stretch its legs. This 2025 Ford Mustang GT RTR Spec 3 has accumulated only 6,500 miles since being purchased new in May 2025.Cars & Bids is currently auctioning the car from Kamas, Utah, with the sale scheduled to end on September 16. It comes with a clean Carfax vehicle history report and a clean Utah title, although there is currently a loan on the vehicle that will be satisfied using the sale proceeds.AdvertisementAdvertisementLow mileage is only part of the appeal here. Between its supercharged V8, heavily upgraded chassis, and spectacular color-shifting paint, this isn't the kind of Mustang GT you're likely to mistake for one leaving the local Ford dealership.RTR Turns The Mustang Up To 810 HPImage Credit: Cars & Bids.A standard 2025 Mustang GT's naturally aspirated 5.0-liter V8 produces 486 horsepower and 418 lb-ft of torque, which is plenty for most people. This car received RTR's Spec 3 package, which includes a Whipple supercharger, dual-pass intercooler, and high-performance fuel injectors, giving it a serious performance boost.RTR rates the resulting package at a mighty 810 horsepower, although Cars & Bids notes that no dyno sheet is included to independently confirm that figure. Power reaches the rear wheels through Ford's 10-speed automatic transmission.That represents a 324-hp increase over the stock engine's rating. Considering all of that power still goes exclusively to the rear tires, applying it effectively should be an entertaining exercise.It Isn't Just About Straight-Line SpeedImage Credit: Cars & Bids.RTR didn't stop after bolting additional horsepower onto the Coyote V8. The Spec 3 package adds Tactical Performance lowering springs, adjustable front struts, adjustable rear shocks, and adjustable front and rear sway bars.AdvertisementAdvertisementA set of 20-inch wheels and an RTR body kit further separate it from a regular GT. The underlying Mustang also has Ford's GT Performance Package, while the cabin features leather upholstery, a 12.4-inch digital instrument cluster, and a 13.2-inch infotainment touchscreen.The seller is including the RTR certificate of authenticity and window sticker, along with a Whipple tuner and RTR suspension adjustment tool. Service records, two keys, and the other listed documentation will accompany the car as well.That Paint Cost Nearly $15,000Image Credit: Cars & Bids.Arguably the Mustang's most immediately noticeable feature isn't under the hood. Its color-shifting Mystichrome finish was a hefty $14,995 option for the 2025 model year.The seller says paint protection film has been applied to the exterior, which has also received a ceramic coating. Tinted windows complete the cosmetic changes, while the interior is finished in Black Onyx.AdvertisementAdvertisementCars & Bids doesn't list any known flaws in its auction description. That's encouraging for a 6,500-mile performance car, although prospective buyers will naturally want to judge its condition from the listing and accompanying documentation themselves.Now The Market Decides What It's WorthImage Credit: Cars & Bids.The Mustang is being offered by its original owner, who purchased it new in May 2025. At the time of writing, bidding has reached $50,000 with several days remaining.Where the final number lands should be interesting. Modified performance cars don't always recover the money spent creating them, but this one combines an RTR package with extremely low mileage and an unusually expensive factory paint option.Whatever someone eventually pays, 810 horsepower from a supercharged V8 is an appealing proposition, and a lightly used RTR Spec 3 certainly isn't an everyday sight on the secondhand market.AdvertisementAdvertisementIf you want more stories like this, follow Guessing Headlights on Yahoo so you don't miss what's coming next.