For some reason many online shops don't do well with listing rotors or pads that fit the PP cars when you do a make/model search.
For example. on
www.tirerack.com, if you want to find front rotors that fit. Set your vehicle to a 2004 STi. That'll show you all the right size rotors that are drilled in 5x100.
For front and rear pads, I think you can set your vehicle to any STi from 04-14.
Rear rotors are a little trickier unless you know the model number to look for.
The Centric 'High Carbon' rotor that fits the rear is part# 125.47043
For brake pads, you can find a lot of options by looking up the industry standard 'shape' designation.
Front pads are shape D1001
Rear pads are shape D961