Next week, Las Vegas turns into aftermarket heaven.

Roll out the rally cars, billion-horsepower engines and every conceivable electronic device -- and some you couldn't imagine -- replica rattlesnake seat covers, bamboo floor mats and more rims than a junkyard and you'll begin to picture SEMA, the Specialty Equipment Market Association trade show.

Anything and everything that can be affixed, attached, screwed on or bolted down to a car or truck is on display at the private show, which begins Tuesday and runs through Friday.

Most car manufacturers will have specialty vehicles at the event, of which Ford Motor Co. is the titled sponsor.

While tough economic times have dampened enthusiasm and participation for many trade shows, SEMA is holding its own. Participation is down about 10 percent (but better than initially expected), but organizers and participants say they're excited.

"There's a whiff of optimism this year," said Peter MacGillivray, SEMA vice president. "I think people are coming to this show with low expectations, and they're going to be surprised with how many people are attending and how many are presenting."

There's certainly good reasons for 1,700 companies to want to participate in the show, which includes 125 presenters. Last year, aftermarket sales hit $32 billion.

Detroit will certainly have a strong presence with General Motors Co., Chrysler Group LLC and Ford all planning on bringing big wheels.

Ford, in partnerships with a number of customizers, will debut a number of show cars, including a 1934 hot rod with Ford's EcoBoost engine.

"SEMA is important for Ford," said Brian Wolf, director of Ford Racing. "It's not only about making great cars, but those enthusiasts who want to take their cars beyond manufacturers' abilities."

Chrysler will offer up race versions of its popular Challenger, a tricked-out and dropped Ram and a pair of Wranglers, one designed for a camp site and the other with off-road capabilities that practically make it ready for a moon landing.

Foreign carmakers have big plans too. Lexus will debut its first supercar in Vegas, the LF-A, while Suzuki Motors America and Kia Motors Co. intend to display rally racers. Hyundai will display its very tunable Genesis Coupe and other vehicles.

While the big-name automakers will use up a lot of space, there will be more little companies offering their wares than big ones.

Traditionally, most companies at SEMA are small businesses, which are more agile at adapting to new technology.

"There have been times carmakers have introduced something that was already outdated by the time the car arrived," MacGillivray said.

Indeed. The 2010 Nissan Pathfinder has a compact flash slot in its stereo.

This year, SEMA will include some themes not typically associated with hot rods, though they should be. SEMA will try to draw attention to new safety devices, green technologies and automotive consumer electronics.

"Lots of features like safety belts, airbags and radios were aftermarket items first," said MacGillivray, noting hybrid and diesel sales are expect to triple by 2013.

Wixom-based NxtGen Emission Controls, along with partner ATS Diesel, will introduce new performance enhancements for diesel trucks that provide more power and cleaner emissions.

Organizers said the show is not just about high performance. When times are tough, people put more money into their cars.

"We've been calling it, 'putting cash into your clunker,' " said Shari Gold, a SEMA spokeswoman. "SEMA is no longer just about performance and customization. It's also about functionality."