You do not have to use anti-sieze. The Subaru vacation pix only suggest using motor oil on the threads and in doing so make sure to only apply 1/3 of the specified torque when screwing them in.
It actually says "the torque should be reduced by approx 1/3 of the specified torque". WTF does that mean ? It could be interpreted as using 2/3 of the specified torque, right ?
I've always used anti-sieze and full torque, with no problems so far, but good tip !