Drilled or Slotted Rotor Facts:
Drilled or Slotted rotors have more grip - Stock rotors not as much
Holes or slots help air ventilation and expel heat. Rotors will run cooler and cool off faster - Stock rotor will over heat sooner and stay hot.
Slots increase brake pads bite - Stock rotors do not. Note: The misconception out there is that slotted rotor will heat up because of the added bite and the rotors will over heat. Yes this is true under repetitive use such as on a racetrack or slowing down a heavy load down a steep hill, and the rotors do not have enough time to dissipate the heat. You need heat for the brake pads to work. The problem is, when there is too much heat, the increased bite provided by the slots will raise the brake pad temperature slowing down the vehicle sooner, thus you don't need to be on the brakes as long.
Holes and slots Reduce Wear - Another misconception is that the slots and holes will wear out the pads sooner. Yes this can be true if you use cheap brake pads that have a low working temperature. The reason is, that for every 100 degree increase over the pads operating temperature, the pad wear doubles. So for example if the pads can only withstand 300 Degrees and your brakes are running at 400, then the pads will start to wear quickly. If you purchase a set of Performance rotors you need to also purchase a set of good performance pads. This will insure longer life of both rotors and Pads
Holes and slots eject water and prevent Brake Pad hydroplaning - Stock rotor can hydroplane in bad weather.
Holes and slots vent gas during brake fade - Stock rotors will fade if the brake pads out-gas.
Drilled rotors are lighter - No real advantage over a stock rotor on a road vehicle.
Drilled rotors are more prone to crack - Well Stock Rotor can crack too if exposed to excessive thermal shock (Fast Heating and Cooling). Note: SP Performance Rotors have an Exclusive Sinusoid curved chamfer that is designed to relieve the stress formed at the edge of the hole to prevent cracking.
Slotted or Cross Drilled Rotors have less surface area - Yes Stock Rotors have more surface area but the added grip and cooling provided by the holes or slots, compensate for the reduced surface area. Note: More is not always better. Stay away from Drilled Rotors that have so many holes that they look like Swiss cheese. Not only is the surface area of the rotor been excessively reduced, but structural integrity of the rotor can also be compromised.
Drilled and Slotted Rotors are more expensive - Not really. You can often purchase a good set of Drilled or Slotted Rotors at the price you would pay for stock rotors at the dealer. Note: I mean a good set of performance rotors, not the imitation bargain rotors. What do you mean by imitation performance rotors you say? Well, most of the inexpensive performance rotors found today on the internet or eBay, are what I call imitation performance rotors. These are cheap, low grade rotors that are drilled and slotted to give you the look, but really not the performance. These are low quality rotors with holes or slots. Remember the old saying, "You get what you paid for".
Ok, durability, cooling, and more grip is all good, but that is not what is important. The important fact is that performance rotors will reduce stopping distance. Let say your vehicle take 30 feet to come to a stop with stock rotors. Then, let's say a set of good high performance rotors will give you a performance gain of 30%. In 30 feet that will be a difference of 9 feet. Those 9 feet can be the difference of your front bumper not slamming into the rear bumper of the car in front of you. So consider spending just a bit more now and save, save, save in the long run.