Earlier this month, I was in Las Vegas for SEMA Show 2004, the premier automotive specialty trade event of the year. This year, more than 100,000 members of the $29 billion industry from more than 100 countries stormed the Las Vegas Convention Center to see more than 1,100 new car parts, tools, and components, all over 2 million square feet of exhibit space.

But here's the key stat: According to SEMA (the Specialty Equipment Market Association), retail sales of aftermarket parts for the compact performance segment alone have grown more than tenfold to $3.2 billion in 2003 from $295 million in 1997.

Now, hot-rodding cars has long been an American tradition. But the latest hypergrowth trend involves a The Fast and the Furious-inspired surge in the popularity of Japanese import car culture. The key consumer in this segment -- ages 16 to 30 -- owns a vehicle with a small-displacement engine, usually with four cylinders and displacing less than three liters. Commonly used vehicles include Honda's (NYSE:HMC) Civic, Integra, and Accord; the Mitsubishi Eclipse; and the Nissan (NASDAQ:NSANY) Sentra, as well as a couple of American cars -- the Ford (NYSE:F) Focus and General Motors' (NYSE:GM) Chevrolet Cavalier.

Last year, participants spent the $3.2 billion on things such as aftermarket wheels and tires, body kits, turbochargers, intakes, and exhausts in an effort to make their sport-compact cars faster, more fun to drive, better looking, and unique. Nowadays, zillions of replacement parts are readily available for a wide variety of Japanese makes and models. In fact, it's been said that you can build a Honda Civic entirely made from parts you can purchase over the counter.

Compact performance market growth*
Year Revenue Growth**
1997 $295 million N/A
1998 $438 million 48.5%
1999 $756 million 72.6%
2000 $1.2 billion 58.7%
2001 $1.5 billion 26.5%
2002 $2.3 billion 55.9%
2003 $3.2 billion 35.2%

*Source: SEMA

**Year over year

Naturally, as an investor, I began thinking about what kinds of companies would make for attractive investments. Unfortunately, many of the obvious places to look -- such as turbo manufacturer GReddy/Trust and wheel manufacturer Rays Engineering -- are either privately held or aren't publicly traded in the United States. Fortunately, there's a company not specifically associated with import hot rodding that still stands to benefit from its surge of popularity.

eBay Motors: the used car marketplace
Here's another key stat: An estimated 60% to 65% of consumers in the compact performance segment acquire their cars used. According to Jim Spoonhower, SEMA's vice president of market research, the market broke down like this in 2003:

Consumer's age New Used
16-17 38.5% 61.5%
18-19 24.5% 75.5%
20-21 30.4% 69.6%
22-23 42.4% 57.6%
24-25 40.0% 60.0%
26-30 57.3% 42.7%

Enter eBay (NASDAQ:EBAY), arguably the greatest business of them all.

eBay Motors is eBay's marketplace for the trade of cars and car parts, with almost all of the cars being used. Like the rest of eBay, eBay Motors is attractive in that buyers can generally buy used cars cheaper than they can at the used car lot, and sellers can sell cars for more than their trade-in value at the local dealership. eBay's network effect is also in play, as more buyers attract more sellers, which in turn attracts more buyers and sellers.

eBay Motors is by far the company's largest segment, accounting for about one-third of overall gross merchandise volume (GMV). At the same time, it remains one of eBay's fastest-growing businesses, outpacing overall growth. GMV at eBay Motors has doubled over the past six quarters and tripled over the past eight. Here are the annualized numbers:

Year Q1 Q2 Q3 Q4
2004 $8.7B $9.8B $10.7B
2003 $5.3B $6.3B $6.7B $7.5B
2002 $2.5B $3.2B $3.8B $4.3B

The problem with eBay has never been business quality. It has always been price. The stock, at 70 times next year's earnings, might even seem normal for eBay. Although the company clearly isn't anywhere near done growing, its stock now carries a whopping $73 billion market cap -- something to consider if you prefer investing in smaller companies, as I do.

eBay isn't the only company poised to capture consumers' appetites for fashionable speed: I'll reveal some others in Part 2 of this series. If you're looking for something to read in the meantime, check out more Fool coverage on eBay:

Fool contributor Jeff Hwang owns eBay shares. The Motley Fool has a disclosure policy.