not sure if the Brakes on the MP3 are the same ones as on the 03 MSP but if they are, then you can just install 2002 Mazda 626 with the 2.5 v6. They are a direct swap for the MSP fronts. Now if you really wanna be a baller. the MS6 and mazda6 fronts can be bolted on as well. but you'll also have to install the rotors. basically it's a factory big brake kit for us Proteges!!!
actionjackson posted a DIY piston caliper boot rebuild somewhere here, search for it... hope you can get away with 25 bucks!