Few names within the Porsche world and historical past carry the load as that of Hans Mezger. His engine design and structure outlined Porsche’s golden age of motorsports, serving as the muse for numerous endurance racers and street-legal legends. It was Mezger’s engines that propelled the Porsche 917 to victory at Le Mans again in 1970 and ‘71, adopted by the 935’s dominant stint within the World Sportscar Championship and 936’s wins at Le Mans within the late Seventies. The Mezger unit additionally helped outline Porsche’s Group C stint with the 956 and 962 within the early Nineteen Eighties and later influenced the mid-engined 993-based GT1 Evo.
By the early 2010s, nonetheless, Porsche’s engineering priorities had been shifting in the direction of extra emissions-compliant powertrains and new platforms. Whereas the GT program for the 911 developed into the 991 and past, it was the 997 GT3 RS 4.0 that grew to become the ultimate chapter to Porsche’s Mezger legacy and is essentially the most highly effective naturally-aspirated flat-six engine ever fitted to a street automobile, setting it aside from each different 911 GT3 RS mannequin. In consequence, collectors right this moment view it not simply as one of many best 911s ever made, however as a milestone for the German model, the place Porsche’s engineering, racing roots, and analog character converged for the final time.
Porsche 997 GT3 RS 4.0: The Closing Mezger-Engine 911
Porsche took the wraps off the GT3 RS 4.0 in 2011, and it was a significant milestone for Porsche’s GT-boss, Andreas Preuninger, and his group in Weissach. The GT3 RS 4.0 was no components bin particular and featured some fairly substantial upgrades over the usual GT3 fashions of the time. This track-bred 911 was outfitted with the {hardware} and learnings that Porsche had gained by way of years of endurance racing and the 911 GT-Sequence growth packages.
Underneath the hood, a high-revving 4.0-liter naturally-aspirated flat-six engine that put out 500 horsepower and 339 pound-feet of torque. Constructing upon the three.8-liter mill discovered within the commonplace 997.2 GT3 RS’s 450 horsepower, the 4.0 now got here with titanium connecting rods, cast pistons, and the identical crankshaft that was used within the 911 GT3 RSR race automobile. A 6-speed guide gearbox (the one transmission on supply) with taller gearing designed for circuit racing sends energy to the rear wheels, with the sprint to 60 mph occurring in simply 3.8 seconds, and prime pace was rated at 193 mph. Sitting on 19-inch light-weight cast aluminum center-lock wheels wrapped in sticky high-performance tires, it carries a Nürburgring time of seven:27 minutes, making it sooner than the Carrera GT’s time of seven:32, again within the day.

However in typical RS trend, energy and pace are solely half the story. A Porsche RS mannequin is incomplete with out top-drawer aerodynamic and weight-saving options. The GT3 RS 4.0 featured light-weight carbon-fiber entrance trunk lid and fenders, bucket seats, light-weight carpets, and light-weight facet and rear home windows, saving 22 kilos. The outcome: a curb weight of simply 2,998 kilos, with a full tank, with the power-to-weight ratio at 5.99 lbs/hp. For context, that is lighter than a 997 GT2 RS’s 3,020 kilos, regardless of packing extra race-ready {hardware}. The present 992.1 GT3 RS ideas the scales at 3,268 kilos.Â
Extra race-derived components come within the type of light-weight springs and aluminium struts, a decrease trip top, wider observe, extra ball joints on the lowerlevel of the rear axle, and a considerable fastened rear wing with redesigned endplates, and air deflection vanes on the entrance bumper (flics), the first-ever on a Manufacturing Porsche, which boosts downforce. At pace, these aerodynamic options can generate 426 kilos of downforce at prime pace.
997 GT3 RS 4.0 Specs
Engine Displacement | 4.0 L |
Engine Configuration | Naturally aspirated flat-6 (Mezger) |
Horsepower | 500 hp @ 8,250 rpm |
Torque | 339 lb-ft @ 5,750 rpm |
Transmission |  6-speed guide |
Curb Weight | 2,998 lbs (with fluids, DIN) |
0–60 mph | 3.8 seconds |
Prime Velocity | 193 mph |
Market Worth And Funding Developments

Porsche solely constructed 600 models of the 9972. GT3 RS 4.0, with wherever between 126-141 models coming to the USA, and it carried an MSRP of $185,000 (~$257,000 inflation-adjusted) again at launch. Given its rarity and the halo standing of the Mezger engine, the GT3 RS 4.0 has now change into one of the sought-after Porsches of the fashionable period. Just some years again, a well-kept instance might be discovered for round $350,000.Â
These days at the moment are lengthy gone. As of 2025, low-mileage automobiles with intensive documentation are altering palms for north of $650,000. Examples with ultra-low miles or a singular spec can command as a lot as $750,000. In accordance with Traditional.com, the common market worth for GT3 RS 4.0s bought over the previous 5 years is $554,413. However the doubling in values will also be attributed to some extra components. Past the shortage and the ultimate swan tune within the Mezger lineage, that is additionally the final analog RS earlier than Porsche adopted electrical steering, PDK, and digital driver aids.
What To Look For Earlier than Shopping for A 997 GT3 RS 4.0Â

Should you’re out there for a GT3 RS 4.0, intensive documentation definitely could be important, given the robust collector attraction. Be careful for modifications that deviate from the manufacturing facility spec. Porsche’s certificates of Authenticity, unique gross sales paperwork, window sticker, and repair historical past are all must-haves. The engine, whereas sturdy, was primarily designed for observe work, and there’s a likelihood that the automobile was pushed arduous. Bore scoring, RMS Seal leaks, and over-rev, potential to realize from the DME report, are all issues to examine earlier than buying.
As for the spec, in typical Porsche trend, the presence of manufacturing facility choices like PCCB (Porsche Ceramic Composite Brakes) or front-axle carry system can considerably affect values. Paint-to-Pattern (PTS) automobiles are notably uncommon, with solely 39 produced. This PTS GT Silver instance with simply 341 miles is presently listed on duPont REGISTRY for $2.7m. Nonetheless, even the usual GT Silver, Carrera White, and Basalt Black examples carry weight, particularly towards the contrasting red-and-gray graphics, distinctive to the GT3 RS 4.0.
A Mezger-Engine Purchaser’s Shortlist

Should you’re prepared to look past the 997 GT3 RS 4.0, you’ve got a number of trendy Porsche icons with the Mezger contact.
Porsche 996 GT3 RS
- Manufacturing Years: 2003–2004
- Manufacturing Numbers: ~682 models worldwide
- Common Market Worth (Previous 5 Years): $206,762Â
Porsche 997.1 GT3 RS
- Manufacturing Years: 2007–2008
- Manufacturing Numbers: ~1,106–1,909 models (410: USA Supply)
- Common Market Worth (Previous 5 Years): $236,663
Porsche 997.2 GT3 RS
- Manufacturing Years: 2010–2012
- Manufacturing Numbers: ~1,500–2,000 (541: USA Supply)
- Common Market Worth (Previous 5 Years): $246,159
Supply: Porsche, Traditional.com
FAQ
1. What was the final Porsche to characteristic the Mezger engine?
A. The 997 GT3 RS 4.0 is the ultimate manufacturing Porsche to characteristic the Mezger flat-six engine.
2. What number of 997 GT3 RS 4.0s had been made?
A. Solely 600 models had been produced globally, with wherever between 126 and 141 models delivered to the USA.
3. Is the GT3 RS 4.0 funding?
A. Sure. On account of its rarity, naturally aspirated Mezger engine, and analog purity, values have steadily climbed and doubled since its launch in 2011, and are anticipated to proceed rising.
4. What makes the Mezger engine particular?
A. The Mezger flat-six was derived from Porsche’s intensive motorsport program and is thought for its sturdiness, dry-sump lubrication, and high-revving nature.
5. Are there different Mezger-powered 911s value accumulating?
A. Sure. The 996 GT3 RS, 997.1 GT3 RS, and 997.2 GT3 RS all characteristic Mezger engines and are thought-about extremely collectible.