well, i've certainly gotten an education from all of you that provided answers. some additional research i've done has provided me with the decision to go with a slightly higher priced rotor than the $20 unit.
not the fact that higher priced means anything. be that as it may, i went with a Wagner ($45) for this go-round. the car (z-28) has 150k, so i figure it was time to retire the original rotors.
one of my thoughts concerning this is that, with the option of purchasing a $20 rotor, i'd change the rotors out everytime i change pads - i would never expect to get 80/100/150 k miles out of a set of $20 rotors.
the Z is my daily driver and i dont "dog" the car. i drive as sane as the next "ordinary" driver. dont get me rwong, i do occasionally get her up to speed out on the back roads.
obviously, i want to match the proper components for this style of car, with "good value". i dont want to over-extend myself financially because i do not weekend-race this car and i dont push it to its absolute limit.
as a point of contrast, i have a 90 Trooper with which i did a complete brake overhaul. i replaced everything: rotors, pads, calipers, master cylinder ... i used the $20 rotors on this vehicle because i *rarely* use it. mostly only to pick up stuff at the hardware store. (i cant remember the last time i started it up:) so with this vehicle, i figured the $20 rotors will be sufficient.
but i have a concern on the Z28 because of its daily use. (the 64 Buick LeSabre convertible will not get the $20 drums :)
thanks for all the input - i appreciate it!
regards, michael