One week in on my swap and i am very pleased. Pedal travel is much better. Response is soooo much better, and feels much more accurate. I like that i can feel the pad takeup and that it takes just a brush with my toe to get the pads to the rotor instead of the 6ft it felt like before.
Install went great. If i didn't have a 5yr old wanting my attention every 2 minutes i would say that i could have had the job done in 2 hours max. The only difficult part was pulling the old booster out (it didn't want to pop past the the plumbing).
Some thing to think about:
-the silver line that's in the way is an aluminum A/C line so try not to bend it to much or you will have refrigerant leaking out.
-when you get ready to pull the old MC and booster, i found it easier to unbolt and separate them from each other. BUT, to get them separated easily, step on the pedal to remove any residual booster vacuum. The legacy booster vacuum is open to the back of the MC so they will be stuck together (there is an o-ring seal between the two while your new booster is a separate sealed unit from the MC). I also separated the MC from the booster going in.
-when both boosters are out, measure the distance of the clevis/pedal pin hole to the back of the Legacy booster and duplicate that on the new booster. This saves you from having to adjust the pedal travel and spacing in the car.
-the new WRX MC is of course bigger in OD by about .5 inches and sits flatter against the firewall. This means that it is VERY close or actually touching the brake lines that run up the back. Protect these from rubbing thru.
-Spend the $60 and get a pressure bleeder. I'm kicking myself for not buying one earlier. It took longer to jack up the car than it did to bleed the system.
I'll add more if i can think of anything.