Takes about six quarts. Based on your location I"d run 10w30 or 10w40 in it. You don't want to skimp on oil quantity, quality, or change interval, because of your timing chain tensioners.
Service tech at local Subaru dealer recommended 5W30 all year for our location.
Our typical winter temps are 50-60F daytime, 32-36 night. Summer daytime can range from 75F to 102F, night around 50-60F. Note that we get about 3-4 weeks of very hot sunny days every summer (90-102F). I'd say our weather is quite moderate, but not very warm.
A member at USMB Subaru forums, the3rsss, recommended 0W30 synthetic over 5W30 for the following reason:
"I believe soa calls for 5w30 for that engine. Remember, the second number(30) is the weight or flowability of the oil at OPERATING temp, approx 210 degrees. this never changes from alaska to texas, once an engine warms up they ALL run at about 210 deg. The first number(5) is the cold start weight. 5 is kinda of an all around middle of the road number. In a warm climate you could use a 10w30, moderate 5w30 and cold 5 or 0w30. Dont mess with the 30 unless your engine is well worn. Now synthetics.....a 10w30 synthetic will flow as well as a 5w30 dino oil cold. Synthetics flow much better at all temps. Your in a warm climate. I would use 0w30 with a quality (not fram) filter. The top of the line purolator (i think its puregard) has a bypass valve opening that is as close to a stock filter as you can get. If you want more info go to www.bobistheoilguy.com
or the petroleum quality institute www.pqiamerica.com
Would synthetic offer that much more protection and performance benefit given our weather, and how much more expensive is it?