Am I bein scammed?

Jsolo

Several hundred miles at least, and several heat cycles (tire allowed to cool down completely). Also, it's the middle of winter, why are you driving with summer tires? I realize it's probably been warm in NY too, but mornings are cold, and really, the tires are not reaching the same temperatures they do when it's in the 50's-80's outside.

Aside from that, did they road force balance them? Michelin's tires are usually pretty decent. In fact, when I run them on the bike, I don't need any weights at all, or very small (1-2 squares).

You mention they're on the rear, what's on the front? If the level of grip of front vs rear tires is drastically different, your car will handle funny.