Okay, it's time for a new set of brakes on my '91 V1500 sub. I have been looking online, and kinda like the idea of drilled/slotted rotors. My only concern is that I do a lot of offroading. Mud, dirt, and sand. How much of an issue am I going to have with them? I worry about mud and dirt packing into the slots and holes. Anybody have any input?