We'd been pacing the Stingray for more than a mile. You know the type: Brand-new, metallic paint, droptop on chrome wheels. Bald spot in the driver's seat. The beloved Baby Boomer ritual—the Saturday night summer cruise in the perfectly polished ride.

Bald-spot hit the on-ramp. I looked over at my friend Dale in the driver's seat. He knew what to do.

It's generally rude to blow the doors off your fellow motorist in a sneak-attack display of overwhelming thrust. So let's frame the decision differently: How else to display the Callaway AeroWagen's defining feature—the shooting-brake rear bodywork—to our Corvette brethren?

I'd like to tell you our fellow 'Vette driver flashed a grin and an enthusiastic thumbs-up as we ripped past. Unfortunately, by the time I found him in my door mirror, he was a vanishing speck. If the AeroWagen's looks didn't register a reaction, its 757 horsepower surely did.

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DW Burnett / PUPPYKNUCKLES
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"We don't call ourselves a tuner," Reeves Callaway, founder of Callaway Cars, told me a few days earlier. "A tuner takes an aggregate of parts that already exists, bolts them on the automobile, and calls it a customization. Everything we make is made specifically for the car. And we manufacture it ourselves."

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DW Burnett / PUPPYKNUCKLES
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DW Burnett / PUPPYKNUCKLES

This particular AeroWagen sports plenty of those custom components. The drivetrain is upgraded to Callaway SC757 spec, featuring a 2.3-liter supercharger peeking through the hood, fed by a new high-flow intake and improved intercoolers; a sport exhaust smooths and amplifies the 6.2-liter V8's song. Callaway says the package adds 107 horses and 127 lb-ft of torque to the stock Z06 on which it's based, good for a face-flattening 2.8-second 0-60 and a mid-10-second quarter-mile.

All these mods are covered by a warranty that augments GM’s factory coverage. Callaway ’Vettes are sold new by GM; maintenance is handled by approved Chevy dealerships, an agreement in place since the 1980s. "We recently had our 30-year warranty review," Reeves told me. "We were sweating bullets. It turned out the warranty incidence on Callaway cars, over the whole period, was exactly the same as the standard car. And some of those cars weren't so good to begin with," he chuckled. "Ours and theirs!"

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DW Burnett / PUPPYKNUCKLES

So, Callaway has a lengthy partnership with GM, a focus on Corvettes, and in-house design and manufacturing. This 757-horsepower rocket-hammer is still shocking. Everything works just as it did from the factory: You can call up Eco Mode on the console dial and get the same softened throttle response and conservative transmission mapping as on the factory car. At the other end of the knob, Track Mode, along with its five sub-setting traction control system spanning wet and dry conditions, still works the same magic through GM's adaptive Magnetic Ride suspension and electronically-controlled limited-slip differential. With electronic driving aids turned off, of course, it's easy to overwhelm the 335-width rear tires (Michelin Pilot Sport Cup 2s, same as the Z06); thankfully, when engaged, GM's traction control is quick-thinking enough to keep up with every burst of no-lag torque.

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DW Burnett / PUPPYKNUCKLES

"There's always a little bit of engineering headroom left," Reeves told me. "The trick is to use up the headroom without using up the reliability."

The SC757 package is mighty and impressive. With its eight-speed automatic, this bright red example charges to redline and chucks off upshifts almost quicker than you can think. The brassy tuba-on-a-rampage exhaust note of the normal Z06 is replaced by a less percussive, slightly more European sounding roar that's louder but not overwhelming. The run up the tach is a constant surge, no gaps or peaks, the platonic ideal of supercharged engines. Driven back-to-back with a stock Z06, the SC757 feels like it's running around under some kind of gravity-reducing force-field.

But with all due respect to the Callaway's 757 horses, they aren't what make this machine so unique.

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DW Burnett / PUPPYKNUCKLES
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The AeroWagen profile takes the Corvette's familiar lines and stretches them like warm taffy. The squat roofline, hunched over a beefy C-pillar and gun-slit rear window, counteracts the C7's rear heft, balancing out the yardage of quarter-panel that props up its uphill beltline.

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DW Burnett / PUPPYKNUCKLES
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DW Burnett / PUPPYKNUCKLES

This major visual transformation is accomplished by a single piece of bodywork. The AeroWagen roof is one giant carbon-fiber molding, filling the hole left by the stock hatchback and mounting to the factory hinges and hardware. It's a complex component to produce; "if you sneeze wrong while you're laying the carbon fiber by hand, it’s gonna show,” Reeves told me. Every angle of the piece is visible—the entire unit, from B-pillar back, lifts up when you pop the trunk, so there’s nowhere to hide defects or shoddy workmanship. The glass is all DOT-compliant, utilizing the C7's stock rear side glass; the rearmost window even has defroster lines. In my week with the AeroWagen, the custom bodywork was as snug and silent as a factory Corvette. The Callaway body conversion costs $15,000, including factory-match paint and installation, with no impact on targa top function. Any model of hardtop C7 Corvette can be converted to AeroWagen form, whether it's stock or .

Despite the dramatic, squinty shape of the rear window, the AeroWagen has exactly the same rearward view from the driver's seat as a standard C7. There's a mild increase in cargo capacity, although taking full advantage of it will block the rear-view mirror. And the drop-on boxy roof generates slightly less aerodynamic drag than the stock bodywork on a C7 Z06, mostly thanks to the AeroWagen's lower-profile rear spoiler.

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DW Burnett / PUPPYKNUCKLES

This particular Corvette, with its SC757 engine upgrade and AeroWagen body, lives in a unique realm. Modified cars with 700- horsepower aren't the rarity they once were; a fistful of automakers now offer vehicles that break that barrier from the factory. Individually, each member of the 700-and-up club is special; taken as a group, they seem to point toward an increasingly commonplace trend.

The AeroWagen avoids that. With the substitution of a single body panel, it becomes visibly unique, whether you're in the driver's seat or in its dust. Reeves agrees. "No matter how much horsepower you have, you get used to it," he told me. "It's the same with speed. Go down the highway at 150 mph. Within a few hours, that's your median."

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DW Burnett / PUPPYKNUCKLES

So customers go looking for something unique, something exclusive. "I think there's always going to be room for the specialist," Reeves tells me. "By necessity, what we do is going to cost a little bit more, and that's antithetical to the mainstream direction of the automobile. Maybe that's the role of the specialist: Put a little bit of cost back into the car."

I think the AeroWagen nails it. It's a unique, functional, painstakingly detailed and high-quality add-on that completely changes the visual character of the car. It's a nod to the favorite offbeat niche of exceedingly offbeat gearheads. When you pull up, people's first question isn't about the horsepower, the 0-60, or the price. The first inquiry, slightly incredulous, is what's that?

In an internet world where everyone's seen everything, that seems like reason enough for the AeroWagen to exist. It's bound to stay that way, at least for the foreseeable future: Callaway currently produces AeroWagen drop-ons at the pace of about one per week, though future improvements could speed that up to one a day.

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DW Burnett / PUPPYKNUCKLES