If we were forced to sum up the GTR in a word, it would be sharp-and we don't mean that in the colloquial sense of "good looking." We mean the GTR gives the C6 edges where there were none and a suggestion of speed. The jutting-jaw front fascia, for example, appears to be ingesting air (and maybe racetrack cones), even when the car is stationary. The widened fenders, meanwhile, complement the design by visually lowering the roofline, giving the car a sportier stance.
In short, the GTR looks like it's either going 200 mph or will be there very shortly-and with its modified LS3 V-8, rubbing up against the "double-hundy" mark is within the car's capabilities. The engine is one of Specter's Matrix II packages. On the LS3, that means a stroker displacement of 416 ci (6.8 liters), a new camshaft, and a replacement of the stock cast rotating parts with heavy-duty forged components. When finished, the engine is filled with Mobil 1 synthetic oil, just like all of Specter's engines from at least the past 10 years.
A custom tune keeps the reconfigured LS3 cheerily ingesting a just-right ratio of air and fuel, breathing through the stock intake manifold and throttle body. Specter says the engine makes about 535 emissions-legal horsepower and about 530 lb-ft of torque. The suitably strong stock drivetrain allows Specter to use the original transmission and axle components without modification.
"The Corvette has very strong components right off the showroom floor," Nowicki says. "The transmission and rear axle are absolutely strong enough for the Matrix II engine."
And while C6 GTR No. 1 boasts a 100-horse gain over stock, the engine package is not standard. The underhood upgrade is an option, one of several offered. Nowicki says powertrain performance is very personal for Specter's customers, and because the GTR can be built on a base model, a Z06, or even a ZR1, leaving the horsepower options open makes the most sense from a business standpoint.
In fact, there's more power to be mined from the LS3. Nowicki told us the Matrix II in GTR No. 1 had a relatively mild camshaft, and that flywheel horsepower of 600 or more could easily be attained with a more radical grind.
"We anticipate that most people will want at least some type of performance increase, but it's best to let them decide," he says.
But while engine output is up for debate, the suspension and braking systems of the GTR are not. Each model receives a Hotchkis stabilizer bar kit to improve cornering reflexes, along with a quartet of StopTech brakes-15-inch slotted rotors with six-piston calipers in the front and a 14-inch/four-piston setup in the rear. Hanging from those beefy rotors is a set of Forgeline wheels (HREs are available, too) wrapped with Michelin's excellent Pilot Sport 2 Zero Pressure tires.
Those Forgeline wheels, by the way, are the first set manufactured with "blind" bolts. This means that the hardware usually seen around the perimeter of wheel center is moved to the inside of the rim for a cleaner look. It was a special request of Specter Werkes, and we think they're on to something. The wheels look great without the bolts. As for the PS2 tires, they're just about the grippiest set of rubber this side of racing slicks. And despite their super-low-profile aspect ratio, they're surprisingly compliant and quiet on the road. On the GTR they measure 285/30ZR19 in the front and 335/25ZR20 in the rear, the same as the ZR1.