While online auction sales of many individual engine components are down from the first and second quarter of 2007, one item has steadily risen throughout the year: complete engine packages.

In the first quarter, online auction sales of complete engine packages averaged $2,514,000, according to data from Terapeak, a developer of market-focused research software that monitors online sales and auctions. Sales then rose 3.6% in the second quarter thanks to a strong April that helped offset softer sales in May and June.

Through July and August, sales are up 2.1% over the second quarter.

The offerings are largely domestic, with Corvette, Viper, Mustang and even some NASCAR engine/transmission packages the most popular sellers, with smatterings of sport-compact (Honda, Dodge Neon) and diesel-truck combinations rounding out the top picks.

Do online sales tell us anything about how parts move across countertops from brick and mortar retailers? Maybe.

Patti Freeman Evans, a senior analyst who monitors the retail industry for JupiterResearch, explains that while online sales are only a fraction of actual retail transactions, the Internet is a key influencer in buying decisions.

"We see online retail plateauing at 10%–15% of total retail down the road—about double the penetration that catalogs ever got," Evans says.

She notes that as online commerce sites continue to develop more sophisticated tools to make purchasing easier and safer, some consumers will shift more of their wallet online.

"But that growth will really be organic, not dramatic. We look to the Internet to remain a highly influential channel for retailers to affect customer purchasing regardless of what channel the actual transaction occurs in."

Terapeak's Motors P&A Research provides sellers with access to comprehensive research on the past year of online auction data and allows users to get in-depth research reports on the competition and themselves. More at