There is reputed to be an inverse relationship between the size of a man's penis and the horsepower, size, and/or flashiness of his automobile. Riding an extremely loud motorcycle, driving a gigantic lifted pickup truck, or operating any year/model of Chevrolet Corvette is said to be a sure sign of men with teeny penes.
Unfortunately, the converse is not true; men who drive minivans are assumed to be lacking in testicular enormity and indeed masculinity, while men in small, "cute" (e.g. Mazda Miata, Volkswagen New Beetle) vehicles are believed to be homosexual. The former tendency has been promoted to sell SUVs, the latter muscle cars; both have more markup than something small and efficient with the same power to weight ratio and a lower sticker price.
While there are no known studies of any possible correlation, a 2004 survey by Tesco Personal Finance claims that 80% of women believe there is a link between the size of a man's car and his ego.1
Also a single by Supermodel, available on the I Wouldn't Piss On It If It Was On Fire compilation.2
References:
- Evans, Tom. Top 10 sexy cars for men to drive - as chosen by women. MSN cars, December 16, 2004. (http://cars.uk.msn.com/News/Top_ten_article.aspx?cp-documentid=475369)
- Album: I Wouldn't Piss On It If It Was On Fire. All Music Guide, retrieved 200904151342. (http://www.allmusic.com/cg/amg.dll?p=amg&sql=10:wcfqxqt0ldse)