Also important to note, Subaru's AWD system is picky as hell and a tread depth difference across the axle is actually pretty likely to damage your diffs or transmission.
Meaning, if you need to replace a tire, you replace all four tires or else run the risk of catastrophic damage to the vehicle. The AWD works great and it's a good system but it can and will screw you out of a thousand bucks worth of tires with no warning. Pros and cons.