Slotted and/or cross drilled rotors dissipate heat much faster than your stock rotors so they stop you faster and don't warp
NO,,, Drilled/Slotted rotors have nothing
to do with cooling, and "finned" rotors don't Warp anyway....
The purpose of the holes or slots is to Vent gases that are produced, under heavy braking, and "push" the pads off the rotor surface. IMHO, slotted are as good for venting for our trucks and eliminate the cracking that can occur with holes.
Brake pulsations are caused by the difference in the rotors surface, as the pads slide on them, "gripping" better/worse. Cutting the rotors gives you an even surface so it eliminates the pulse, but there was no warp. Proper Bedding of the surfaces prevents the problem in most cases.
REAR Brakes, in our unloaded trucks, aren't doin' $hit in the first place
don't waste your money. They suffer more from corrosion, because they are so "unworked", then anything else (the inside of the rotors, against the dust shield stays lumpy & crusty because it doesn't get used enough (unless you drive a lot of miles or tow/haul weight))
The Fronts always do the majority of the work, especially empty, and if you want to improve braking that's where to do it (although with good tires/pads/rotors our brakes are really pretty good!)