This question has come up before. Subaru manuals are easily found on the Subaru website.
"Towing with all wheels on the
ground
1. Release the parking brake and put the
transmission in the neutral position (CVT
and MT).
2. The ignition switch should be in the
“ON” position while the vehicle is being
towed.
3. Take up slack in the towline slowly to
prevent damage to the vehicle."
"For CVT models, the traveling
speed must be limited to less
than 20 mph (30 km/h) and the
traveling distance to less than 31
miles (50 km). For greater speeds
and distances, transport your
vehicle on a flat-bed truck."