It's always funny when Impreza's "drag" race, considering they are totally not meant for that. A Mustang should hand an Impreza there ass in a straight line, considering that is what mustangs are for. Stock for stock you should beat a wrx, if he has a full exhaust (catless) and if he is a good driver he could do high 13's is my guess. With a dyno tune, lower that a little. Now if he has alot of mods, He could take m3's and KB'd Mustangs all day, *speaking from experience*