2013 SRT Viper (© MSN/Rod Hatfield)

This is a new era for the automobile, one in which the ear-splitting exhaust sound of a V10-powered supercar being revved to redline supplants the wistful rhetoric of a pollution-free future filled with cars running on sustainable energy.

Automakers have tempered their fixation on fuel economy and are rolling out new sports cars and high-performance coupes at a brisk pace. It's a sign that the economy, and the companies themselves, are on the upswing, experts say.

Nearly as many unveilings at the 2012 New York International Auto Show seemed to focus on high performance as on hybrids, electric vehicles or 40-mpg engines. It's a continuation of a trend seen at other auto shows in recent months.

More coverage from the New York International Auto Show

"It's almost as if the 'green' is just factored in," says Derek Jenkins, design director at Mazda in North America. "It's like, 'Yeah, 40 miles per gallon — whatever.'"

Make no mistake, the message of efficiency is still clearly at the forefront of new unveilings, but it's no longer the focal point it once was. Performance and driving excitement have come back to light, evidenced by the debut of the SRT Viper and Jaguar's announcement that it will create a new sports car, the F-Type.

"We've been kind of out of the true sports-car business for too long," says David Pryor, brand vice president for Jaguar North America. "The XKR-S is an incredible performance car, but it's not a purely focused sports car. So that's where for us to bring a car like the F-Type, we've wanted to do it for a number of years, but I think everything is coming together with the investments that we're making in the business, with the new ownership, with the economy getting better, with just what is taking place with this brand. It's really almost like the perfect time; the stars are aligning for us."

Watch Video:  New York Auto Show Highlights

Yet with all the passion around performance, a balance must be struck; fuel economy is important, even for tire-scorching sports cars. That's why companies such as Bentley are unveiling cars such as the Continental GTC with a V8 engine that is 40 percent more fuel-efficient than the original version, which has a huge 12-cylinder engine.

It's also why Mercedes-Benz is adding start/stop technology, which shuts down the engine during temporary stops, to its high-performance AMG models, such as the SL65 AMG unveiled in New York. "Our incoming engines are smaller, yet more powerful than what they replaced, and even more fuel-efficient," says Rob Moran, AMG product manager. "It's kind of like you can have your cake and eat it too, with absolutely no calories."

That is critical to ensuring the future of the sports car long term. In the meantime, here is a roundup of the latest high-performance vehicles to debut here in the Big Apple.

View Slideshow:  2012 New York Auto Show: Top 10 Cars

Bentley Continental GTC V8

The Bentley Continental GTC V8 has a 4.0-liter V8 engine that upholds Bentley's philosophy of effortless power while bringing new levels of efficiency to the brand. It puts out 500 horsepower, yet it shuts down half of its cylinders when full power is not needed and uses an 8-speed automatic transmission to help achieve 40 percent better fuel economy than the original Continental GTC , which has a 12-cylinder engine. Performance is still high: zero to 60 mph in 4.6 seconds and a top speed of 188 mph. The Continental GTC will go on sale this summer for $174,000 alongside the previously unveiled GT coupe, which costs $191,400.

Read Blog:  Driving the Bentley Continental GT V8

BMW M6 Convertible

BMW unveiled the M6 Coupe in Geneva, ahead of the convertible shown in New York, but it's the drop-top that will hit showrooms first in June. The coupe and M5 sedan will follow a couple of months later. All three are powered by a 560-horsepower twin-turbo V8 engine that produces around 10 percent more horsepower and 30 percent more torque than the V10 engine it replaces, yet is 30 percent more fuel-efficient. It will be paired with a new 7-speed dual-clutch transmission and differential to optimize power transfer to the pavement.

View Pictures:  BMW at the 2012 New York Auto Show

Mercedes-Benz SL65 AMG

Mercedes doesn't expect to sell many SL65 AMGs, nor will they be that much faster than the V8-powered SL63 AMG that debuted in Geneva. That makes the production of this new twin-turbo 6.0-liter V12-powered roadster all the more awesome. It is the rarest of rare SL roadsters for the most avid AMG enthusiasts. Output is an astounding 621 horses and 738 lb-ft of torque. It sprints to 60 mph in 3.9 seconds. Tweaking the turbochargers, cylinder heads, engine mapping and ignition coils not only helped boost output by 17 horsepower over the previous V12, but also helped reduce emissions and fuel consumption. A 7-speed transmission with new fuel-saving technology and a reduction of 254 pounds to the overall weight of the car further aid efficiency. This is the first AMG model to get a new twin-blade front grille, which will make its way to future models. The SL65 AMG will go on sale this fall. The version shown in New York is a special anniversary edition, of which only 45 will be sold worldwide.

View Pictures:  Mercedes-Benz SL65 AMG

Shelby 1000

The latest creation of Shelby American Inc., a Las Vegas-based company owned by the legendary Carroll Shelby himself, is the Shelby 1000. It is based on the Ford Mustang Shelby GT500. Only 100 will be built, including a street version with about 950 horsepower and a track version, called the Shelby 1000 S/C, with more than 1,000 horses. Getting that much power isn't cheap: First you need a $54,200 Mustang Shelby GT500. Then you need to pay Shelby American $149,995 to create the street version of the Shelby 1000, or $154,995 to create the track version. The entire engine and drivetrain is reworked, literally down to the nuts and bolts, which are beefed up to withstand the monstrous power. The car's suspension and other chassis components are also upgraded. It's the most potent muscle car in history that bears the Shelby name.

Read Blog:  Shelby Boosts Mustang to 1,110 HP

SRT Viper

The sense of anticipation in the crowd before the unveiling of the new Viper was overwhelming. They raptly listened as SRT Chief Executive Ralph Gilles spoke of its various improvements in both performance and quality. "I don't even know where to start," he said at the beginning of his presentation. "It's like being pregnant for almost 24 months." After his spiel, he drove the new Viper out on stage, got out and kissed the front fender amid cheers, applause and whoops from the audience.

Watch Video:  The Viper Returns

The new Viper is even more badass than before. Its 8.4-liter V10 engine puts out 640 horsepower and 600 lb-ft of torque. The body structure of high-strength steel is 50 percent stiffer and 28 pounds lighter than before. The exterior body is 32 percent lighter, thanks to a carbon-fiber hood, roof and rear decklid, and aluminum doors and sills. The interior is a huge step up; the seats are the same as those in a Ferrari. A racing version also debuted, driving out on stage with a deafening roar and filling the expansive room with exhaust. It will compete in the American LeMans series.

View Pictures:  New SRT Viper

Matthew de Paula wanted to be an automotive journalist ever since reading his first car magazine in grade school. After a brief stint writing about finance, he helped launch ForbesAutos.com and became the site's editor in 2006. Matthew now freelances for various outlets.