very mildly warped rotors normally won't be noticed or cause a shimmy. But if it is more than mild, often will cause a shimmy at higher speeds, especially on the front axle. However a few caveats. Fixed calipers are much more sensitive to the effects of warp, the rotor moves back and forth against a fixed caliper so warp is often more noticeable. With a floating caliper, the caliper can move with the rotor and not be as noticeable. I don't know if the MDX has fixed or floating rotors. Sometimes vehicles are a mix, fixed on one axle, floating on the other.No, warped rotors will not cause a misbalance, but they can produce a shimmy. The wheels are off the car for the balancing, so the rotors are not part of the equation, but throw the wheels back onto the car and now the rotors are. I have to say though, even badly warped rotors should have a virtually indistinguishable impact. You'd have a much greater chance of noticing a bad CV joint/axle. A motor mount or transmission vibration can be mistaken for a balance issue as well. That said, if you didn't have the issue before the new tires then it would take a huge coincidence for the problem to pop up right after and not be directly related to the tires. One other challenge of course is the heightened senses that occur after knowing a change was made and something that was there before, but you didn't notice, is now noticeable because you are hyper sensitive.