The Subaru Outback sedan looks like any other midsize car, with a trunk and comfortable seating for four adults. But Subaru is tweaking some parts of the Outback sedan and wagon this year to meet the specifications of a light truck, the same regulatory category used by pickups and sport utilities. Why? Largely to avoid tougher fuel economy and air pollution standards for cars. It is the first time an automaker plans to make changes in a sedan — like raising its ground clearance by about an inch and a half — so it can qualify as a light truck....