If you’re headed to the upcoming Monterey Car Week and are a staunch Porsche enthusiast, here is a car you’ll want to take out time to see. On Friday, August 15, at the Porsche Classic Restoration Challenge during Werks Reunion, Porsche Santa Clarita, part of Galpin Motors, will unveil a 2007 Porsche 997 GT3 that has been transformed by Manthey Racing into something you’re unlikely to find anywhere else in the United States. Manthey, of course, is Porsche’s own racing and motorsports outfit based near the Nürburgring.
This build was inspired by “Grello,” the legendary 911 GT3 R known for its distinctive lime-green livery and its impressive racing record, including multiple class wins at the Nürburgring 24 Hours and dominance in various endurance races. This latest 997 GT3 MR reimagines that immensely race car as a street-legal tribute to one of Porsche’s most successful and iconic motorsport machines.
This 997 GT3 MR (Manthey Racing) build goes far beyond visual upgrades. Based on the 997 chassis, widely considered the last of the analog 911s from the famed Mezger era, its original 3.6-liter flat-six was shipped to Manthey in Germany and rebuilt to a 4.2-liter unit. Power has gone up from 415 to 523 horsepower, thanks to a GT3 R intake, 997 Cup manifolds, an Akrapovič exhaust, an upgraded rotating assembly, and an ECU tune.
Extensive work has also been carried out on the chassis with Manthey-spec KW coilovers, and control arms now work with a custom alignment to deliver sharper response. The conversion to center-lock hubs with BBS E88 wheels means you’ll spend less time swapping tires and more time driving. Larger brakes should offer better performance on the pavement, while helping shave off precious seconds during timed track sessions.
“This build represents the pinnacle of what’s possible when we honor Porsche’s heritage while pushing the boundaries of performance,” – Beau Boeckmann, president and chief operating officer of Galpin Motors.
But perhaps the most striking aspect about this build has got to be the exterior paint. The Kameleon paint from House of Kolor flips between turquoise and purple, catching light in unpredictable ways. A Manthey front spoiler, GT3.2 rear wing, and the distinctive “4.2” end plates convey that this is far more than a stock 997 GT3.
Inside, Porsche Santa Clarita teamed up with CarBone to create a unique cabin that draws inspiration from Porsche’s Sonderwunsch (Special Wishes) program, renowned for their bespoke builds. Magenta Alcantara contrasts purple carpeting, GT3 RS bucket seats replace the standard seats, and you get a more modern 991-generation sport steering wheel. A CAE short shifter capped with a purple heartwood knob adds a dash of mechanical flavor. The centerpiece of this vivid analog cockpit is a 1968 Heuer Super Autavia motorsports clock, where you’d normally find a Sport Chrono.
Beau Boeckmann of Galpin Motors calls it “the only Manthey 4.2 build of its kind in the country.” Manthey-built street cars in the U.S. are already rare, and a 4.2-liter 997 GT3 MR is almost unheard of. So here’s a question: if you owned a car like this, would you keep it as a collectible or wring it out on track? With Manthey’s upgraded hardware under the skin, it’s tempting to do both. Either way, this one-off GT3 MR should draw a crowd the moment it’s unveiled soon.
Images Source: @GalpinMotors, Porsche