911 GT3 (997)

Why Porsche kept two engine families

By the time the 997 arrived Porsche was building two different flat-sixes for one car. The Carrera used the M96 and M97 engines with their intermediate-shaft bearing; the Turbo, GT2 and GT3 used an older architecture descended from the 911 GT1 race engine and credited to Hans Mezger, the engineer behind the 917's flat-twelve. RM Sotheby's catalog copy describes the difference plainly: a simpler bearing design with pressure-fed lubrication, dual timing chains, and an engine overbuilt for road use because it was developed for racing. Stuttcars notes that Porsche had never meant to carry two engine ranges for the 911, and the 9A1 engine of 2009 was the rationalization that was supposed to end it. The GT3 was the reason it did not end quite yet.

997.1: the RS comes to America

The 997 GT3 was unveiled in 2006 and sold here as a 2007 model. Porsche's own retrospective gives 415 hp from 3.6 liters, an 8,400 rpm limit, 0-60 mph in 4.1 seconds, 193 mph and 3,075 lb, helped by aluminum doors and luggage lid. It was the first GT3 with PASM adaptive dampers and the first with traction control. The GT3 had reached North America only with the 2004 model year 996, and no earlier RS had been sold here at all. The 997.1 GT3 RS of 2007 and 2008 changed that. Sports Car Market puts it at 1,169 built with 452 for this market, at a US list price of $123,000.

997.2: 3.8 liters, center locks and two new options

Porsche Cars North America announced the 2010 GT3 in January 2009 at a base price of $112,200. Displacement rose to 3,797 cc, VarioCam now worked on intake and exhaust, and output went to 435 hp with 317 lb-ft and an 8,500 rpm limit. Stability control was standard for the first time, switchable in two stages. The wheels moved to a single center-lock nut, a design Porsche had previously kept for cars like the Carrera GT, saving about 6.6 lb a set. Two options arrived that shape the used market today: dynamic engine mounts filled with magnetic fluid that stiffen when the car is driven hard, and a front axle lift that raises the nose 1.2 in (30 mm) at speeds up to roughly 30 mph. Porsche kept the weight at 3,076 lb. MotorWeek tested one at 4.1 seconds to 60 mph and 12.2 seconds at 118 mph in the quarter mile, and listed it at $114,450 with gas guzzler tax.

The 3.8 RS

The 2010 GT3 RS followed at the Frankfurt show in September 2009 and went on sale here in spring 2010 at $132,800. The US release gives 450 hp, 15 more than the GT3, with shorter gear ratios that deliberately give away top speed, dynamic engine mounts as standard, a wider track front and rear, a titanium exhaust and an optional lithium-ion battery that saves more than 22 lb. It was the homologation basis for the racing GT3.

RS 4.0: the engine line reopened

On April 28, 2011 Porsche Cars North America announced a final car limited to 600 worldwide. The 4.0-liter engine took its crankshaft unchanged from the 911 GT3 RSR, with titanium connecting rods and forged pistons, for 500 hp at 8,250 rpm and 339 lb-ft. Carbon fiber front fenders and luggage lid brought it to 2,998 lb with a full tank, and the dive planes on the front bumper were a first for a production Porsche. It was priced at $185,000 before destination. Stuttcars records that the line building the Mezger engine had already been shut and had to be reactivated to make these 600 engines. The 991 GT3 that followed for 2014 had a different engine and no manual gearbox.

Coolant pipe fittings are the fault every guide leads with. On the Mezger engines in the GT3, GT2 and Turbo, certain coolant fittings are bonded into their housings with adhesive rather than welded or mechanically fastened. Heat cycles eventually defeat the glue, and the failure mode is a sudden dump of coolant, which on a track means coolant under the rear tires. Stuttcars and The Stable describe the same cure: remove the fittings and pin or weld them. Both call it the single most important check on these cars, and a car with documented pinning or welding is worth more than one without. It is an engine-out or engine-lowered job, so it is commonly done with a clutch. The rear main seal is the other shared item. The Stable's guide describes RMS leaks as a common finding on 997.1 cars and notes the repair is normally combined with clutch work because the seal sits between engine and gearbox. What the engine does not have is the intermediate-shaft bearing and bore-scoring exposure of the 997.1 Carrera engines; both guides and RM Sotheby's catalog copy make that distinction. The center-lock wheels on 997.2 cars use a multi-tooth central bolt and a nut with a locking ratchet that Porsche says prevents the wheel coming loose even if the nut was not properly tightened. No source fetched for this page documents the service torque or the replacement interval, so those are left unstated here; they are in the owner's manual and the workshop literature. Likewise nothing fetched gives a GT3-specific clutch life or a US cost for front axle lift or dynamic engine mount repair. As a general running-cost marker, one RS 4.0 catalog records a four-year major service in New York at $4,400.

Start with which car it is. A 2011 GT3 and a 2011 GT3 RS share the 3.8 but not the body: the RS uses the wide shell with a wider front and rear track, 9-inch and 12-inch wheels, shorter gear ratios and, by the US release, 450 hp against 435. The RS 4.0 adds carbon fiber front fenders and luggage lid, dive planes on the front bumper and a numbered plaque out of 600; RM Sotheby's catalogs quote the number, and a car's paperwork should agree with it. Options matter more than usual. Front axle lift and dynamic engine mounts were both new options on the 997.2 GT3, the mounts were standard on the RS, and PCCB ceramic brakes were optional throughout. A Porsche Certificate of Authenticity and the original window sticker settle what a car left the factory with, and auction catalogs for these cars list both as a matter of course. A DME report of engine over-revs is the other standard document: the RM Sotheby's Arizona car was sold with a report showing no over-revving in any of the six ranges, and a specialist buyer's guide treats an over-rev history on a manual car as a serious red flag. Ask whether the coolant fittings have been pinned or welded and who did it. Ask whether the car has been tracked and what was replaced afterwards. On a 997.2, ask who has had the center-lock wheels off and how they were tightened. The Monterey 2025 RS 4.0 carried a note that California emissions rules required sale to a dealer or an out-of-state resident, so a California buyer should check a very low-mileage car's status before bidding. Color counts on the RS: RM Sotheby's described one 2011 car as believed to be one of 26 US deliveries in Aqua Blue Metallic with Guards Red graphics.

All figures are US dollars, as of September 2026. classic.com benchmarks the five variants at $146,083 (997.1 GT3), $247,558 (997.1 GT3 RS), $170,660 (997.2 GT3), $344,131 (997.2 GT3 RS) and $790,190 (GT3 RS 4.0). Recent US sales it lists run above those benchmarks. 997.1 GT3: $183,000 on PCARMARKET in August 2026 for a 2007 car with 40,000 miles, and $253,250 on Bring a Trailer the same month for an 8,000-mile 2007. 997.1 RS: $352,500 on Bring a Trailer in June 2026 with 12,000 miles, and $237,440 at Bonhams in Greenwich, Connecticut in May 2026 with 33,000 miles. 997.2 GT3: $240,000 in July 2026 for a 2010 car with 47,000 miles and $270,000 in May 2026 for a 2011 with 17,000 miles, both on Bring a Trailer. 997.2 RS: $572,500 on Bring a Trailer in July 2026 for a 10,000-mile 2010. RS 4.0: $995,000 at Broad Arrow in Costa Mesa in April 2026 with 5,000 miles. Lot pages fetched directly from RM Sotheby's add three-figure-mileage cars: a 2011 RS at $406,500 in Arizona in January 2023 (374 miles, premium included per Sports Car Market), another at $412,000 from the White Collection in 2023 (490 miles), and RS 4.0 number 394 at $1,077,500 at Monterey 2025 with under 160 miles. Dealer asking prices on the same pages sit far higher and are not sales.