First introduced to the U.S. in 1975, the BMW 5 Series has never wavered in its mission as a midsize car that functions equally well as a luxury liner and a performance machine. As such, it has long been the benchmark by which other premium sport sedans and wagons are measured. The first 5 Series sedan was powered by an inline six-cylinder engine, a tradition that continues to the current day, as the 2007 BMW 5 Series offers a pair of refined and potent inline sixes as well. Of course you can also get a V8. Until 2005, all 5 Series sedans and wagons sold in the U.S. were rear-wheel drive; BMW added all-wheel-drive (AWD) versions to the lineup for 2006. In fact, the 5 Series wagon is now available only with AWD.