My '12 Impreza gets well north of 40mpg in highway driving, has AWD and "CVT" transmission (actually a six-speed auto). Also a '20 Impreza that gets a little over 35mpg highway, but does better on surface streets. Same engine, 7-speed "CVT". The '20 has roof rack rails but nothing's mounted on them so they shouldn't affect aerodynamics much.But those were much more primitive vehicles than the more recent, AWD Subarus, which are heavier, usually have larger and more powerful V6 engines, automatic transmissions, and typically get about 24 mpg in mixed driving and maybe close to 30 mpg under ideal conditions.