WKM

My new 2009 IS350 is a great ride but the steering is driving me nuts... On winding roads and long sweeping turns the steering system seems at first not to react to small adjustments, then "over-react", giving a bit too much boost. Almost feels like an electric steering system waiting for a signal from the steering wheel, then getting the signal and moving the wheels too slowly. Can also feel a bit like tires are following ruts in the road. Anyone else have this issue?