I've had them on for ~15k miles, bought them when they had their buy 3 get 1 free deal going on.

I haven't rode in a GP with GR-2's, so I can't compare on that aspect. The ride with the monroes seems fine, you're not lowered so cornerning could be better, but it feels stable. No bounciness. Its actually a little firmer than I would like, but nowhere near unbearable. Just not Buick-esque. Our highways are terrible, and the car feels fine over the bumps. Not squirrely, not bone-jarringly harsh.