Land Rover Repair: updrading rotors, cross drilled rotors, quality pads

Question
I am considering upgrading my rotors on my 02 discovery my dealer says this is a bad idea because it sets off the tc sensor.Is this correct?

Answer
I presume you are talking about switching to the cross-drilled rotors with slots.  These slots can cause accelerated pad wear.  As long as you use high quality pads that don't squeal, you probably won't have a problem.  If the brakes do squeal, however, they can cause a vibration giving an erratic wheel speed sensor code.