All StopTech Balanced Brake Upgrades are shipped with slotted AeroRotors, however drilled or slotted rotors can be substituted for an additional $50 per rotor. Slotting assists in removing the debris generated between the pad and rotor during braking as well as increasing the "bite" characteristics of the pad/rotor interface. A drilled rotor provides the same benefits and works better in the wet, but is more susceptible to cracking under severe usage, as well as causing greater pad wear. Many customers prefer the look of a drilled rotor, and as long as they will only be used for street and occasional light track use, they will work fine. For more severe applications, where elevated rotor temperatures are expected on a regular basis, StopTech strongly recommends slotted AeroRotors. Standard caliper colors are red or black paint. Silver is no extra charge, but requires a 15 business-day lead time. Blue or yellow calipers add $200 per pair, require a 15% non-refundable deposit, and require a 15 business-day lead time. After extensive testing of most of the high-performance street pad compounds currently on the market, StopTech chose the Axxis Ultimate from Australian manufacturer, Bendix Mintex, as the standard pad included with its big brake kits. Testing showed this to be the best pad for the price, for aggressive street and autocross use. When aggressively driven over and over at the company's test facilities, and with dynamometer test results, StopTech found that the pad works cold with minimal loss of coefficient of friction throughout its entire operating temperature range. There is no fade until 850 F and the maximum operating temperature (MOT) is 932F. In contrast, a stock pad typically has an MOT of 700 F. The Axxis Ultimate pad combines cold stopping performance with high-temperature fade resistance and features anti-squeal shims and wear sensors, where applicable. Race pads are optional. StopTech performs extensive testing of all popular pad compounds and is a stocking distributor of several popular pad companies. To help determine which is the best pad for you, please see the street and race pad descriptions in the catalog or contact StopTech directly. 355 x 32mm