2001 CHEVROLET CAMARO User Comment / Complaint

I just purchased 2001 camaro z28 covertible. i have owned camaro's forever and was never anything but completely happy with it. this car has some kind of "shake" to it at certain speeds. the steering wheel looks like someone is in the column shaking it! also it sounds like the springs need some serious help that i did not hear initially. the car only has 37k miles on it. i have only owned this car for a couple of months, brought it back to the dealer twice already and being told that there is no problem except for some kind of a covertible shake issue which completely sounds like a joke and they can't provide the bulletin that they say was issued on this car but was no big deal. i also took it to ase cert. mechanics that are telling me different, i just need some help so i am not taken to the cleaners on this car.