You made quick work of it, nice job. For future interest, I researched cryogenically treated rotors and went with them and Hawk pads last brake change. They use a liquid nitrogen bath to square up the mollecular structure of the metal providing longer life and greater resistance to warping. Fleets like usps use them. I have been very happy (50k mikes now) given all the heavy towing I do.
A quick note on this........Cryo treating helps with strength of the material, as well as overall toughness (the amount of energy it can absorb before structural failure), but does nothing to stop "warping".
"warping" of brake rotors is far and away a myth. The rotors don't warp, or change shape. You can take the worst set of "warped" rotors you can find and put them on a lathe with a dial indicator and you'll find less than 0.001" of runnout. Beyond that, if the rotors were to physically change shape, the calipers in all modern vehicles "float" in relation the axis of rotation. That is to say the caliper would simply move in/out along with the movement of the misshapen rotor. There would be no net effect on the pedal feel, or stopping power.
When you "warp" a rotor, what has ACUTALLY happened is that you have heated the brake pads beyond a destabilization point, and some of that brake pad material has been transferred to the rotor surface. This leads the surface to have high and low spots in terms of thickness. This usually happens from repeated heavy stops, and then sitting stationary. Think stop and go traffic with a heavy braking foot, and then sitting still once they're good and hot. There have been studies done where you can "feel" as little as 0.0003" (Three Ten Thousandths) of inch difference in rotor thickness through the brake pedal. This is because the rotor thickness changes lead to a physical movement change in the distance between the pads, and that directly translates to the hydraulic pressure in the system. This is also what leads to the "surging" feeling you get when this has happened.
What's worse, is that in this scenario, it's a positive feedback loop. Once you have embedded some brake material unevenly on the rotor face, every time you stop, a little more will get added. So the problem continues to grow and grow until you either shave that material back off with a rotor resurfacing, or you replace the rotors with new ones. I personally won't resurface rotors. They are too inexpensive, and you run the risk of shaving too much off and getting past the case hardening (which cryo treated rotors don't have) on the surface. Just get some new ones and move along.
You can avoid this "warping" situation two ways. First is to have properly sized brakes and drive with a light braking foot. Plan ahead, read traffic patterns, and avoid aggressive stop/go situations. A little patience in gridlock traffic goes a long way here. Secondarily, you can properly "bed" the brakes. This is where you go out on a long open section of road and do 3-5 HARD stops from 60+. You want a LOT of heat in the brakes to get the pads to destabilize and deposit some pad material on the rotors. The key here is to do this EVENLY. So get them good and hot, then drive for a few miles without stopping to let them cool back to operating temps. This will put a thin layer of brake material on the rotor, and help prevent that destabilization from happening again, and if it does, there is already pad material there, so you wont add as much as you otherwise would have.
I sat through a brake technology seminar at SEMA awhile back, and this has really stuck with me. Ever since then I've not had a single brake rotor "warp" on me. Proper bedding technique, and properly sized brakes are best, with driving technique being a STRONG player in the problem.
