Carl, the repair shops here use translated Haynes, I checked :-))))))
Most people (here) run 10w-40 for some reason. probably because most of the cars on the road have high mileage and the tolerances on a 120k+ miler are not what they used to be on the maiden voyage of the car :-)
I guess 10w40 flows some but I don't give a s*it. 5w-30 flows better in local (cold) winter and the engine does not have to push thick sludge around. But, then, it's a beater. Still, I'll run 5w30 when my A4 arrives.
I run 20w-50 in my bikes when I lived in bloody hot kaulifornia though.
10w-40 in cars since skiing trips were rare.Is that viscosity-vs-temperature chart so difficult to grasp in adjust to your area temperature ranges?
Also if you leave in the bloody hot sunbelt why the heck do you need subaru to begin with? Get a rear wheel driver, pour your favorite 20w50 in it and have fun.