seems to me you need to jack the car up and have a look around, i havent owned one so i dont know if theres a common problem with these models,has it just started or been getting worse,good luck,cam.:thumbs_up:
sorry,couldnt resist. like cam said, best to jack the car up and have a look, could be a number of things. check the wheel for play, check the driveshaft mounts and gearbox mounts. check the anti-roll bar mounts and drop links ect