Also pull apart the bolts and boots, one caliper bolt on each side has a rubber bushing on the end. Make sure all of these parts are clean and well lubed so the caliper slides on them freely. Make sure you do not have rust on the caliper bracket where the pad shims locate the pads. You should be...
The 548's will work but the 589's are what is in G3 Coyotes due to the potential for higher combustion temperatures with DI and compression. Not really certain how different they are in actual heat range. Information is spotty.
Traction control off doesn't mean the Stability is off. While it will let you spin the tires, it still works very hard to prevent you from hitting a tree in the background.
But you can get the pedal to vibrate under hard braking on the street (panic stop)? Brake pads usually squeal, not the sound you recorded. The sliding rear calipers typically make most of the noise with any performance compound and swerving usually flexes everything enough to push the pads away...
That does not sound like a brake rotor/pad issue. Have you tried swapping wheels and tires around? You have zero ABS lights, you can still get abs to activate etc? Something sounds like it is not tight, and when you apply the brake it is forcing everything back into position. I'd look for...
Yes, the designer tried to take advantage of the landscape. There was a section of flat track I carried so much speed (90mph) a stock S550 drifted 4 wheels and if it went bad it was pine trees. Lots of fun.