Sorry, Hertz, you don't have the market cornered on special edition hot rental cars. You don't even have the market cornered on hot Shelby Mustang rental cars. Not any more, at least. Thanks to a new partnership between Sixt and Shelby.

Rental company Sixt has commissioned 21 special Shelby GT-S Mustangs that it will be offering in Southern California, Southern Florida, and, of course, Las Vegas.

They're more than just that eye-searing Sixt Orange paint job and black stickers too.

The cars get a supercharged version of the Mustang's 5.0L V8. Shelby says that they're a special rental car tune that makes more than 600 hp. The cars will come exclusively with a 10-speed automatic, which is probably a smart move for most rental customers.

There are other upgrades as well. Like a Shelby vented hood with a special front bumper. Plus rocker sill extensions. Inside is special leather and a plaque serializing the car.

Other performance upgrades on the GT-S cars include a Borla exhaust, Ford Performance springs and sway bars, and a Shelby by Brembo front brake kit.

They'll be built this summer, and become available to rent the same season. Once they're done with their tour of being the fastest cars in the world, they'll be up for sale. Though they might need some new rear tires.