Unless you want to go to the expense of bigger wheels, (go on, you know you do..

), the only calipers that will fit are those off 99 onwards cars, with "SUBARU" in relief down the front of the caliper.
They are 4-pot and need the discs that go with them, but will fit under your wheels.
Try breakers, but they are becoming rare, so don't expect cheap
Alcazar