"Don't forget to bed your new discs in properly, which contrary to usual belief is best done with used pads, although this may not be possible because of the condition of the pads !! This process is known as Tempering and changes the composition of the steel in the discs. Steel atoms are grouped into tiny crystals, and brand new discs are comprised mostly of MARTENSITE which are long and thin Crystals, this type of steel is very hard but prone to cracking and warping with excess heat. By tempering the steel you'll change the MARTENSITE into a CEMENTITE and FERRITE combination which are more rounded, fatter crystals, this isn't as hard but less brittle and much less likely to crack and warp.
To do this it's a matter of heating up the brakes slightly and and letting them cool slightly; find an empty stretch of road drive at about 60mph brake with medium pressure to about 30mph. Don't stop as the cooling flow of air is important, continue driving moderately for 2 minutes and then repeat the braking process at least 10 times. Now stop for at least 3 hours so the disc cool down completely. When they have run through the cycle again this time with firmer braking pressure, stop and let the disc cool completely for a few hours again and go through the process again 10 times with even firmer braking, let them cool down again and for the 4th set of ten runs brake harder yet again. Your discs should then be almost fully tempered, but it's best to avoid really hard use for at least 500 miles. After this the discs should be able to cope with as much use as you can give them. I would say 99.99% of people don't even know about this yet alone do it, and explains why many people fit new discs and before they know it they complain of the discs being warped."