I am considering buying a new 2005 Subaru Impreza WRX. While pondering the AWD concept and looking at the Subaru manual 5-speed transmission I asked myself a question. Let’s say you have 30K on a set of tires. You hit something in the road that ruins one of the tires. If you were to buy one or two new tires how would the small difference in size affect the driveline. You don’t have to replace all four tires? Also, I am use to getting around 60K to 70K from my FWD cars. How many miles can Subaru’s AWD system get from a set of tires?