If you want to "upgrade" your rear brakes, a recommended way is to do the Legacy GT/H6 rear disc upgrade. It consists of the larger Legacy rotor and a new caliper bracket. Your existing caliper can be used in the new bracket.
Best thing to do is check the good 'ol technical forums for more info on it.
There's also the old legacy turbo rear vented rotor "upgrade", but that is a much more involved process which requires new rear calipers due to the wider vented rotors. Again, this info is contained in the "brakes" technical forum.
As for the fog lights, I'll confirm, that they are H3 bulbs. I don't recommend getting bulbs larger than the stock 55 watts. Anything more powerful, and you run the risk of possibly melting the housing and/or starting a fire!
Of course, if you've rewired your fog lights and aren't running the thin stock wires, then run whatever you want.