my question is two parts...

first , i altered my work out to allow more time for cardio.... For each day/body part I am now doing 2-3 exercises, but extending the sets to between 4-7 low reps to burn out on the last couple of sets.... when im done the workout, i feel like i could still do a bit more.. But the next day I am nice and sore..... Is the soreness a good indication of progress and response to the change in the work out?

second, i have read this somewhere, but can someone explain the action time on protine sources... what i mean is whey protine is quick acting, so its good right after a work out.... I believe egg whites are slower acting so they are good for bed time... can anyone elaborate on this??