Another Mustang prototype has been spotted testing and this one appears to have a set of bigger brakes and wider tires than the previous prototype.

We draw your attention to one of the few areas not covered in camouflage. This test pony is riding on a new set of wheels, and we can't help but notice a resemblance to the current Mustang Mach 1. Our spy photographer was able to snap some fleeting images of the 'Stang's shoes as the car drove by, and a very close look suggests the rear tires are 275s – the same width available on the Mach 1. Interesting ... but wait. There's more.

Behind those rear wheels are brakes that look different compared to previous prototype sightings. The discs appear a bit larger, and the dual caliper setup is something we saw on Mustang test mules last year. The Shelby GT500 is the only pony in the current stable that offers a dual-caliper setup on the back, but don't jump to conclusions about this prototype possibly being a next-gen GT500, or even a new Mach 1 for that matter.

In all likelihood, we're looking at a seventh-generation Mustang GT sporting a tweaked performance package. Wheel/tire and brake upgrades are typical of such packages, and we already know V8 power will endure for the foreseeable future. A previous sighting captured a camo-covered Mustang on video, singing the song of its people.

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