I can't stand automatics myself, don't own one, and never have. The ability to get the Outback with a manual is one of the primary reasons we bought it. I've always towed with a manual, but it was always a truck (most recently a Land Rover Discovery), with pretty stout components, and decent off idle torque figures...
GVWR on the trailer is 2990 lbs, boat dry weighs 2100, so when you figure in the trailer weight (steel) and fuel, yes, it is right at 3,000 lbs. Trailer GVWR (Boat is a Yamaha LS2000 whose trailer came with the boat, and was manufactured for Yamaha by Shorelander) was so the manufacturer didn't have to put brakes on it (most states in the US require trailer brakes over 3,000 lbs), but it would obviously need them for the Outback to have any chance of stopping safely when trailering.
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~Scott & Nadia
'05 Outback 2.5i Wagon
Willow Green Opal/ Moss Green Metallic
225/60HR16 Bridgestone G009's