Direct from Carbotech FAQ section:
If you have had another manufacturers brake pads on those same rotors; then you will ABSOLUTELY have to replace or resurface (turn) those rotors before installing the Carbotech brake pads.

If the rotors and drums are in relatively good condition, meaning they are smooth, flat, with no visible cracks, deep scoring, distorted, and with no other visible damage; and you have ONLY had Carbotech brake pads on them, then they do not have to be resurfaced or replaced.

Carbotech XP8
A high torque brake compound with a wide operating temperature range (200°F-1350°F+). Carbotech XP8 is the first of our racing compounds. Outstanding initial bite at race temperatures, high coefficient of friction, excellent modulation and release characteristics. Extremely high fade resistance, very rotor friendly with 100% non-corrosive dust. Excellent as a front brake pad for lighter ITA, ITB, ITC, SRF, H4, H5, and other cars that weigh less than 2,400lbs. Perfect for novice, intermediate and advanced track day (HPDE) use with any tire, and can still be driven safely to and from the track. There are several vehicles that use XP8 on the street, autocross, and at track day (HPDE) events. Carbotech does NOT recommended XP8 as a daily driven street pad due to elevated levels of dust and noise. XP8 is also a great rear brake pad for almost any race car (Spec Miata-T1/T2/CMC). XP8 is a great compound on the front & rear of most open wheel and sports racers.

Available Options:
Option:	nonePre-bedded pads
This product was added to our catalog on Friday 06 August, 2010.
Customers who bought this product also purchased Ferodo Super Formula Racing Brake Fluid DOT4 626°F AP Racing J-Hook Front Rotors & Hardware, PAIR AMSZ Max Slot Rotors Disc ONLY, Front pair