From the July/August 2026 issue of Car and Driver.

Stuttgart meets Affalterbach in this matchup of the GT3 against the GT63. The GT3 stands as Porsche's most focused 911 variant, while the GT63 Pro represents the pinnacle of AMG's sports-car range. Mercedes-Benz's AMG arm has long targeted the 911. Can this new model unseat the established sports-car leader?

Beneath the Mercedes-AMG's long nose lies a twin-turbo 4.0-liter V-8 delivering 603 horsepower and 627 pound-feet of torque without any electric assist. This wet-sump V-8 connects to a nine-speed automatic and an all-wheel-drive setup with front-axle disconnect capability.

By comparison, the 911 GT3 carries a naturally aspirated 4.0-liter flat-six in the rear. This dry-sump engine produces 502 horsepower and 331 pound-feet of torque sent solely to the rear wheels via a seven-speed dual-clutch automatic. The Porsche weighs 1058 pounds less than the Mercedes at 3214 pounds versus 4272 pounds, placing just 38.7 percent of its mass over the front axle compared to the AMG's 54.2 percent.

The Mercedes-AMG GT63 Pro starts at $205,550 with our tester at $216,910. Performance features like carbon-ceramic brakes and the Pro's cooled transfer case and differentials come standard for extended track sessions. The sole suspension extra is the $1800 front-axle lift. Michelin Pilot Sport Cup 2R tires and Sun Yellow paint add no cost. Costlier options included AMG carbon-fiber trim at $2850, the Driver Assistance package at $1950, and black nappa leather with microfiber plus yellow stitching at $1900. A black microfiber headliner added $1600, with minor items like the $110 AMG fuel cap rounding out the list.

Jessica Lynn Walker|Car and Driver

The 911 GT3 opens at $239,850, but our loaded example reached $313,010 due to Porsche options. Key weight-saving choices include the Weissach package at $20,490, forged magnesium wheels at $17,840, and carbon-fiber bucket seats at $7270, trimming a claimed 48 pounds total. The wheels save 20 pounds alone, with the rest from seats and the Weissach items like the carbon roof, trunklid, anti-roll bar, and wing. Carbon-ceramic brakes cost $11,330 extra for fade resistance and further savings. The front-axle lift adds $3890 and Cartagena Yellow Metallic paint $1580.

Jessica Lynn Walker|Car and Driver

Interior and Exterior

Porsche pares the 911 to essentials in GT3 form. The optional race seats fit tightly with fixed massive bolsters and non-adjustable backrest angle, though height can be set. They deliver a pure racing feel.

The microsuede-wrapped steering wheel feels taut, transmitting road texture even at rest. The GT3 excels on track with its aggressive wide body, functional vents, and prominent rear wing.

HIGHS: Blazing speed, composed ride, refined cabin.
LOWS: Reduced peak grip, slightly abrupt brakes, higher fuel use.
VERDICT: A capable track machine that doubles as a daily driver.

Jessica Lynn Walker|Car and Driver

From the rear three-quarter view, the AMG echoes the Porsche's silhouette with its wing and roofline, despite the longer wheelbase and forward engine placement. Inside, it mirrors other Mercedes GT models with power-adjustable heated and ventilated seats, rich infotainment, head-up display, and heated wheel. It projects speed yet offers luxury, suiting both track and road use without demanding constant high-performance driving.

For hauling gear, the AMG wins easily. Both allow loose items behind the front seats, though the GT3 Touring offers optional rear seats. Official cargo totals five cubic feet in the Porsche's front trunk versus up to 11 cubic feet in the Mercedes hatch, enough for a weekend trip or shopping run.

Jessica Lynn Walker|Car and Driver

Powertrain and Performance

The AMG pulls ahead in straight-line tests, reaching 60 mph in 2.6 seconds and the quarter-mile in 10.8 seconds at 128 mph. The Porsche trails slightly at 2.8 seconds to 60 mph and 11.0 seconds for the quarter-mile at 125 mph. The Mercedes extends its lead to 160 mph in 18.8 seconds, 2.6 seconds ahead of the GT3, with a top speed of 197 mph versus the Porsche's 193 mph.

Porsche 911 GT3

HIGHS: Exceptional cornering grip, precise brakes, responsive paddles.
LOWS: Firm ride, basic interior, elevated cabin noise.
VERDICT: A precision instrument optimized for its purpose.

Jessica Lynn Walker|Car and Driver

The Porsche's quicker dual-clutch transmission excels in rolling acceleration tests like the 5-to-60-mph run and passing maneuvers by two or three tenths of a second thanks to lower weight and crisp shifts. Its reduced mass also aids braking and cornering, posting 129 feet from 70 mph and 1.19 g on the skidpad against the Mercedes' 137 feet and 1.11 g.

At full throttle the GT63 delivers an 89-decibel V-8 growl. The GT3 reaches 97 decibels at its 9000-rpm redline with a high-pitched scream best enjoyed with a helmet.

Driving Experience

These peak figures overlook finer traits. The 911's minimal sound insulation raises road noise at all speeds, measuring 76 decibels and 37 sones at 70 mph cruise versus the AMG's quieter 70 decibels and 26 sones.

The Porsche brakes respond instantly without thought. The Mercedes shows a slight initial lag then stronger bite that requires attention. Turn-in feels immediate in the 911, while the AMG needs a moment for its extra front weight and longer wheelbase to settle, occasionally hinting at understeer before revealing strong balance.

On rough desert pavement the Porsche stiffens further from its Sport baseline. The Mercedes offers a Comfort mode and a Sport setting that rides more supple than the GT3. The Porsche's control-arm front suspension keeps the nose planted, avoiding typical 911 front-end patter, yet the AMG's softer springs and active roll stabilization provide adaptable handling.

Jessica Lynn Walker|Car and Driver

The Winner Is . . .

Owners with multiple vehicles and ample funds who pick daily based on mood will favor the Porsche 911 GT3. Its minimally adjustable race interior and firm suspension suit track laps perfectly. The sharp responses and detailed feedback define its appeal for flat-out circuit driving.

The Mercedes-AMG GT63 Pro covers a broader performance range. Less specialized than the Porsche, it trails by seconds at Virginia International Raceway's Grand Course during Lightning Lap testing yet proves far more livable for everyday driving, making it the overall victor. This standout model earns its status as the premier GT.

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Specifications

Specifications

2025 Mercedes-AMG GT63 Pro
Vehicle Type: front-engine, rear/all-wheel-drive, 2-passenger, 2-door coupe

PRICE
Base/As Tested: $205,550/$216,910

ENGINE
twin-turbocharged DOHC 32-valve V-8, aluminum block and heads, direct fuel injection
Displacement: 243 in³, 3982 cm³
Power: 603 hp @ 6500 rpm
Torque: 627 lb-ft @ 2350 rpm

TRANSMISSION
9-speed automatic

CHASSIS
Suspension, F/R: multilink/multilink
Brakes, F/R: 16.5-in vented, cross-drilled ceramic disc/14.2-in vented, cross-drilled ceramic disc
Tires: Michelin Pilot Sport Cup 2R
F: 295/30ZR-21 (102Y) MO1
R: HL305/30ZR-21 (107Y) MO1

DIMENSIONS
Wheelbase: 106.3 in
Length: 186.1 in
Width: 78.1 in
Height: 53.3 in
Passenger Volume: 49 ft³
Cargo Volume: 11 ft³
Curb Weight: 4272 lb

C/D TEST RESULTS
60 mph: 2.6 sec
100 mph: 6.5 sec
1/4-Mile: 10.8 sec @ 128 mph
130 mph: 11.1 sec
150 mph: 15.8 sec
Results above omit 1-ft rollout of 0.2 sec.
Rolling Start, 5-60 mph: 4.1 sec
Top Gear, 30-50 mph: 2.5 sec
Top Gear, 50-70 mph: 2.6 sec
Top Speed (mfr claim): 197 mph
Braking, 70-0 mph: 137 ft
Braking, 100-0 mph: 274 ft
Roadholding, 300-ft Skidpad: 1.11 g

Interior Sound
Idle: 50 dBA/6 sone
Full Throttle: 89 dBA
70-mph Cruising: 70 dBA/26 sone

C/D FUEL ECONOMY
Observed: 13 mpg

EPA FUEL ECONOMY
Combined/City/Highway: 14/12/19 mpg

2025 Porsche 911 GT3
Vehicle Type: mid-engine, rear-wheel-drive, 2-passenger, 2-door coupe

PRICE
Base/As Tested: $239,850/$313,010

ENGINE
DOHC 24-valve flat-6, aluminum block and heads, direct fuel injection
Displacement: 244 in³, 3996 cm³
Power: 502 hp @ 8500 rpm
Torque: 331 lb-ft @ 6250 rpm

TRANSMISSION
7-speed dual-clutch automatic

CHASSIS
Suspension, F/R: control arms/multilink
Brakes, F/R: 16.1-in vented, cross-drilled ceramic disc/15.4-in vented, cross-drilled ceramic disc
Tires: Pirelli P Zero Trofeo RS
F: 255/35ZR-20 (97Y) N1
R: 315/30ZR-21 (105Y) N1

DIMENSIONS
Wheelbase: 96.7 in
Length: 179.9 in
Width: 72.9 in
Height: 50.4 in
Passenger Volume: 49 ft³
Cargo Volume: 5 ft³
Curb Weight: 3214 lb