The second-generation Sienna finally joins the minivan mainstream when it goes on sale in March. With available all-wheel drive, seven- or eight-passenger seating, and a fold-flat, 60/40-split third-row seat, it promises to be the first people hauler to truly meetand perhaps surpassthe standards set by the . With a wheelbase that’s five inches longer and front and rear tracks that are four inches wider, the Sienna is no longer a 7/8th-size minivan. The windows in the sliding side doors roll down halfway, and the well-appointed interior is 44 cubic feet bigger than before. The standard 3.3-liter V-6 sends 230 horsepower through a five-speed automatic transmission, and Toyota claims a 0-to-60-mph time of 8.4 seconds as well as 25 mpg on the highway.