At the auto-x I was noticing that pretty much every car had a different spot for the caliper’s position on the disc brake. i.e. The VW’s had them all the way out, so the front was grabbing at 3o’clock and and rear was at 9o’clock. The 911 had them at 3o’clock on both wheels. I don’t recall were the wrx’s are located. Are the WRX’s and STI’s in the same place? Does it matter? One of those things that make you hmmmmm....
My guess would be that the foirce on the caliper would be the same no matter what position at which it is mounted. I assume that the position is determined by other factors, such as what the car designers have to work around. Or maybe its how well the caliper can be braced at certain positions, so that the tangential force is trasmitted more directly up to the frame? For instance, do you evcer see any calipers mounted at the 12 or 6 o'clock position? I don't, as I would imagine this would hafve a very negative effect on how the brake force is transmitted, besides it would probably get in the way of the strut or other suspension parts. Just a hypothesis