Your dealer (OR you if you installed it) should have installed the heavy duty springs. They are black, look in your trunk. If they are grey...take it back.
My car has been great for the most part. I have 7,500mi on it.
I still get 34.6mpg on the highway, can go over 500miles on a tank.
Problems:
Rippled modlings, sunglasses holder stuck.
I have not had any of the other things some people complain about: long cranks, rotten egg smell, headliner creak.
Love the car.