In the "for what it's worth" category, I replaced the rotors on my Ford truck with Napa high end rotors. Not drilled or slotted but better material and better machine-ing to prevent warping (ford rotors are notorious for warping). Just an all around better rotor. 80k miles later still true as can be and perform well. I also rarely use my brakes to control a descent. It's all about the engine braking in tow/haul mode. Just find a good rotor with good reviews. No need to go drilling a bunch of holes in a perfectly good piece of metal.