I can't comment on upgrading the calipers on the fronts, but I have heard that you can replace the rear drums on the Echo with calipers/rotors from an MR2, so you would have all wheel disc brakes.so if you get sport upgraded discs for an mr2 4x100 it should bolt right up. Obviously research needed/googling, but I think you will find it will be possible once u can get confirmation. According to autozone, the front calipers are the same as the MR2 as well.