Back-to-basics, classically styled 911s have become all the rage, prompting Porsche to roll out the 911 Carrera T and GT3 Touring, and the 911 R before them. But prior to all of those came the Sport Classic. And we're not sure whether to be surprised or not, over nine years now since its debut, to see one coming up for auction with a $400-500k estimate.

The Sport Classic was based on the 997 – the most prolific of 911s ever made. But as low-key as it may have been, it stood out clearly from the rest.

For starters, it featured a unique exterior design. It lifted the wider rear end off the Carrera 4 to accommodate its wider track, atop which was fitted a ducktail spoiler. The front end was unique as well, as were the classic Fuchs-style alloys and Zagato-style double-bubble roof. And it was all coated in a special shade of gray, with tone-on-tone gray stripes.

The interior was one of the most exquisite ever fitted to a production Porsche, with brown leather and houndstooth upholstery with light gray piping. And there were changes made to the mechanical components, too.

The 3.8-liter atmospheric flat six was upgraded to 408 horsepower (23 more than the contemporary Carrera S), channeled through an old-school six-speed manual transmission, with a mechanical limited-slip differential and carbon-ceramic brakes.

Only 250 examples were made, of which this was only the second. It's said to have been ordered by a "close friend of the Porsche family" and kept in a climate-controlled garage in California. This despite it never having been officially offered in North America. With only 150 miles on the clock, it's still practically new, and will come up for sale on January 18 at RM Sotheby's sale in Scottsdale, Arizona.