hmm... fiberglass cracks easily, plastic bends. plastic fades funny when painted. i would go carbon fiber, its stronger and wieghs nothing. although that tends to be a bit spendy, and i am not sure how paint would react on it.
There are only a couple body kits out for the 06's. And I'd work on suspension and wheels before putting a body kit on it. You'd be disappointed in how it looks with the stock ride height.
urethane is the way to go man... stock bumpers are urethane... just do lips all the way around full bumper kits don't really capture the essence of subaru but dont take my word for it i can't afford volks and tien coilovers mox
def urethane, fiberglass seems to chip much easier. and when it does you get ugly white chip marks all over