Odd Brake Noise/Feel after rotor install?

[infernosg]

It seems like every time I finally get a noise fixed another pops up...

A couple weeks ago I installed some new Power Slot rotors on all for corners. I couldn't get a number of the set screws out so they were burned out with a torch at a local brake shop. Ever since then the brakes have been making some really low crunching/thumping sounds as I come to a stop when applying anything more than "moderate" (read: normal) pressure. Also, I've noticed that, while at a stop, I can push the pedal all the way to the floor with decent, but not excessive pressure. I'm not really sure if this is something new or just in my head because I switch from driving the RX-7 and a '09 Tacoma.

From what I can tell the master cyliner, brakes lines and calipers are not leaking as I'm not loosing any fluid. Regarding the brake "feel" I'm leaning toward old, water-filled brake fluid (has not been changed since I've owned the car) or possibly a dying the caliper. I'm not really sure what's causing the noise...