please, please, please!!! use the same tires front and back on an AWD.
few years ago I had to put (actually, the insurance company) different
pairs front and back on a 1997 2.2 Sport Impreza MT. few thousands
miles after, the car started to make small sudden pulls with every
shift.... it spent more time at Subaru Service than anything else....
after several attempts without results, some guy at the garage noticed
the tire difference............
problem solved!!!
and just to be more energetic, the 4 tires were same brand, same size,
same specifications, _only_ different tread! Subaru didn't cover it,
and I didn't want to go back with the insurance company. but the
service did cover evreything else they tried ;-)
cheers,
MO