You made no mention of actually spraying down and scrubbing the pistons clean prior to pushing them in... not good. All the abrasive road grit and gunk has now been shoved in to that seal, and may contribute to issues downstream, I.e. spongyness..
I hily recommend every one cleans those pistons well with a toothbrush and brak cleaner prior to pressing them in.
Ymmv
And yes, ebc pads hiss, but they grip well also, after about 200 miles, clean the rotors with brake kleen, and a in after 5k, it will help prevent shudder.