Starting to think about brakes for my 2004 C70. Its got 17 inch wheels, 50k miles. I have the following questions.

1. Short of measuring, is there a way to tell what size rotors are installed?
2. Are the rotors on the c70 "turnable" or are they simply remove/replace items?
3. Are the slotted replacement discs really necessary.... or do they just look cool ( not do downplay the importance of looking cool)?