I'm getting ready to replace the front pads on my 05 C230 Komp Spt sedan with some low dusting ceramic pads and was curious about the rotors. Normally I would have the rotors turned when I change pads but I'm not changing the pads due to wear, I'm changing them because the factory ones make more dust then an Iraqi sand storm, lol. The car has about 27,000 miles on it and I don't feel any shake or vibration from the pedal or steering wheel but how would I be able to tell if I need to replace the rotors since they are cross drilled and cannot be turned? They are however, starting to develop very slight grooves in line with the holes. I can barely feel the grooves with a finger and they aren't shiny or noisy, whadya think? Thank you in advance.