I have a chance to but two new drilled rotors for the front of my 89 635. I will be able to get them for wholesale ($268.00 installed) with new pads. I now have a warped rotor from a driving school, but have no experience with drilled rotors. Should I replace stock front rotors with drilled ones or not? What are the pros and cons? Thanks, Johnny 89 E24, K&N cone filter, Dinan chip, MM 11's, BMP strut bar, etc., and no more money in my checking account!