MOSCOW — In what may be one of the more extreme marketing extravaganzas of the season, Porsche has kicked off the inaugural Transsyberia Rally here, as it unveils a limited edition of 25 Cayenne S Transsyberia models in connection with the event.

Entrants started Friday from Red Square and are expected to cover a 4,412-mile circuit, ending on August 17 in the Mongolian capital of Ulaanbataar.

Among the participants are renowned rallyists Rod Millen, Armin Schwarz and René Metge.

The rally vehicles have been modified in Weissach and include a roll cage, a special air intake on the hood, an underbody guard, additional body sealant, special off-road tires, four roof-mounted headlamps, a roof spoiler and a retuned dynamic chassis control system.

The production Cayenne S Transsyberia will incorporate some of those changes, including specific all-terrain tires, roll cage, shorter final-drive ratio, transverse differential lock, larger underbody skid plate and stronger front control arms.

Updates on the 14-day event are available at the Porsche Transsyberia Web site.

What this means to you: We're assuming the official pace car for next year's Indy 500 already was spoken for, so Porsche settled for the next best thing: a rally from Moscow to Mongolia.