04 low mile, is it still under warranty? If so, have dealer replace, no $$$ out of your pocket. Once they are replaced: when stopping from freeway speeds, let the WJ roll forward a bit after the hard braking so that the heat from the pads is spread out over the rotor.
A highspeed trip down from the Eisenhauer tunnel into Denver with a cool down run on I-70 through part of Denver reduced the warp that I was feeling in my wife's 01 WJ. I'll have to replace the rotors though at some point since I can't get her to let the WJ roll a bit at stoplights.