Come from aerospace manufacturing and had my own "rally car" based business for years. I will not EVER allow some jack ass to "turn" (ruin) my rotors. That is like the old and equally ignorant shade tree belief that certain engines "need back pressure" (exhaust sizing). Only three options, ignorance, chosen ignorance, or you have a business and are ******** someone else to make money. There are many white papers on the subject.
99% of the time when people think their rotors are "warped" what they really have is uneven pad transfer on the rotor from the pad. Usually from pushing a pad compound past it's max thermal threshold, then stopping motion allowing an uncooled pad to "stick" to the rotor. This leaves a deposit on the surface greater than all remaining area on the rotor. Later you attempt to stop and feel the high spot, or pulsation pedal believing the rotor is "warped".
On my mine and customers cars, a quick (but even) use of a wire wheel would remove the deposit and return the performance to normal. Sometimes you could knock the glaze off the pad too, but not advisable and only in a pinch.
Best practice is to just replace the rotors and use a better pad compound. I'm a new 2020 Raptor owner and have not looked into what is available yet. I will say one of the best compounds for spirited daily use I EVER came across was the Ferodo DS 2500 pads for my Brembo equipped Evo VIII. At about $300 a front set they were not cheap, but FREAKIN fantastic for anything short of a real track day/competition. Then depending, DS3000 or better.
Cliff notes:
Never trust a mechanic who believes in turning rotors.
Never "turn" rotors. De-glaze or better yet replace.
Use better pad compound in the firsst place to reduce the issue before its a problem.
