The Detroit Three auto makers will show off bins full of custom parts and a host of vehicle concepts when the annual Specialty Equipment Market Assn. show kicks off today in Las Vegas.

Their aim is to keep the lucrative enthusiast segment excited in an age when small cars and emissions standards are at the forefront of every business decision.

“SEMA has momentum today, as it has had for 47 years, because the desire to customize, personalize and enhance performance is still strong,” says Jim Campbell, General Motors vice president-performance vehicles and motorsports.

GM also boasts some 50 million vehicles on U.S. roads today, he tells WardsAuto at a recent sneak peek of the 39 vehicles and various pieces of performance hardware the auto maker will display SEMA.

The annual SEMA show puts customization ideas from GM, Ford and Chrysler in front of some 60,000 sellers of the items.

The auto makers hope those small-business owners, which comprise most of the $30 billion aftermarket industry, will sell their parts or draw inspiration from the concept vehicles. The show also gives them a chance to test the waters for consumer reception of a potential vehicle or model variant.

GM, for example, has announced production of the Chevrolet Sonic Dusk, a version of the new small car with special additions such as ground effects, spoilers and 18-in. wheels. The auto maker showed the car in concept form at SEMA last year, and today will have the production model on display.

GM also will show a number of small-car concepts. The vehicle segment comprises 59% of the auto maker’s mix at the show.

Other GM wares include crate engines, performance parts and accessories for the Chevrolet Camaro, personalization options for the Sonic, and an active build-your-own crate-engines installation display promoting the GM ownership option.

A Ford Racing Mustang Cobra Jet concept will be the cornerstone of the auto maker’s display at SEMA. The factory-built turnkey drag racer features a twin-turbo 5.0L V-8 engine relying on the same EcoBoost technology Ford uses in production vehicles, powering the racer to an 8.0-second quarter-mile (0.4 km) at about 150 mph (240 km/h).

The Cobra Jet name dates back to 1968, when the National Hot Rod Racing Assn. circuit was experiencing major growth. Ford revived the name for a new factory drag racer in the ’08, ’10, ’12, and ’13 model years. It sells just enough of the cars to keep them eligible for NHRA competition.

Ford says it plans to further develop the Cobra Jet engine technology. “We’re investigating Cobra Jet for a future offering,” says Jamie Allison, director-Ford Racing Technologies.

Ford will show a total of 50 vehicles. Roughly 30% are small or midsize cars.

Chrysler’s Mopar brand parts unit will take center stage at SEMA, and for the first time a Fiat 500, featuring a beach theme, will join concept vehicles based on the Dodge Charger, Jeep Wrangler and Grand Cherokee and Chrysler SRT Viper.

George Goddu, business manager-Ford Racing performance and North America Motorsports, says SEMA remains relevant today because of the connection between auto makers and enthusiasts.

“The enthusiasts are the car people of their neighborhood,” Goddu tells WardsAuto. “They are influencers. So from a corporate point of view, the business case is that we have people going from being Ford fans to being Ford advocates.”

But unlike years ago, when big horsepower ruled every corner of the SEMA show, Detroit auto makers now go armed with small cars. The trend reflects today’s market, where fuel prices are pushing more consumers to smaller vehicles and tighter fuel-economy and emissions regulations compel GM, Ford and Chrysler to build them.

According to WardsAuto data, small cars through September accounted for 19.9% of the new-vehicle market, up from 15.8% five years ago. Middle cars commanded 21.6%, up from 19.4% in 2007.

Campbell says GM is going to the show with mostly small cars because the auto maker’s lineup is much more robust stronger with the Chevy Spark, Sonic and Cruze. “We have a stronger portfolio of cars to create the right platform to offer accessories and enhancements,” he says.

Ford’s Goddu sees the trend, as well. Even the so-called tuners of the last decade, who preferred small, Asian-brand cars as the basis for their customization, are moving into the new breed of compacts from Detroit.

“Those people, to a large degree, have moved out of their Honda Accord with a “fat-can exhaust” and into something more sophisticated,” he says.

“We’re talking about the Mustang here today,” Goddu says at an event for the Cobra Jet. “But we’re just as excited about the Focus ST and the performance that EcoBoost brings to the table right out of the box. We’re developing cold-air kits and exhausts and lowering springs and performance calibrations to small cars. The mix is absolutely changing.”

But don’t expect auto makers to turn their backs on big-engine enthusiasts. In fact, GM recently introduced its family of small-block V-8 E-ROD crate engines and powertrains meeting California emissions regulations.

Ford’s SEMA display will include a ’40 Coupe reproduction promoting availability of the steel bodies from the auto maker. The engine bays are designed to accommodate a modern V-8 or the car’s original flathead V-8.

“Clearly the V-8 aftermarket modifications are still an important element, although the growth for us would be the small-car segment,” Campbell says. “At a macro level, there are more small cars being sold every year, so the small-car parc is increasing every year.”