For DD situations...
Stopping distance: Tires
Pedal feel: Pads / Lines / Fluid / Brace
Bling: Calipers / Rotors
Upgrade as you see fit.
Calipers can help with fade, if that's an issue, but on a DD vehicle, it likely isn't.
Yes, I know tires make the biggest difference in stopping power (been here long enough to read all those threads/arguments), and I am not too worried about pedal feel as long as the brakes work, though I do have the pads/lines/brace upgrade on my to do list. I am not really wanting the bling factor either as I would prefer blank rotors and the calipers to be silver (or graphite) with no logo, I just really dislike the look of the stock mono-pot calipers on the WRX, not to mention that the outside of the caliper (visible, right behind the wheel) shows a deposit of what appears to be light surface rust. I have had 'fade' one time in the car, but it was while slowing from 'way too fast', and I likely will not be doing that again anytime soon.
Willwood makes a four-pot kit for the front that will fit under 17" wheels and are currently developing a kit for the rear.
Wilwood Big Brake Kit Group Buy!
That is nice to know they have an option available, though I don't want 'big brakes' I want better calipers for the stock size rotors. I had surfed through Wilwood's site, as well as Baer's and Brembo's, neither Wilwood or Baer listed any fitment for Subaru.
Brembo had some that fit Subarus, but only the gaudy massive big kits, which is not really what I was looking for, and way too expensive.
I did see that Wilwood had replacement calipers for like '60s through '80s American cars that fit stock rotors, I wonder if any would be compatible? I guess I will have to contact them and ask, seems that they at least have a record somewhere on the full dimensions of the WRX around the wheel/hub/suspension area.
I also saw that Baer had a few kits that are said to fit under like 14' wheels, They are still kind of gaudy, but atleast they are 'normal' sized. Plus, they are better priced than Brembo, but again, no clue if they would fit the WRX wheel/hub/suspension area.
I was kind of hoping that maybe SPT, Hawk, Ferodo, Stoptech, or DBA (I would say STi, but I know those are re-branded Brembos) might have calipers that I was just not seeing in my searches, but they seem to only make pads and rotors.