I have the same car. I HATED the ride with Dunlops. Called Tire Rack. Spent an hour on the phone with him and he concluded that the Turanza and Mich. Energy are great tires, but NOT as soft as the Yokohamas. Soft was my main concern as I came from an LS 400 with 16's on it. I finally bought them for 590. incl. ext. warranty no prorate, lifetime balance, etc. and they are VERY smooth. Did not tell my wife and she rode in it and asked me what happened to the car, it was so smooth. They are equally as quiet. I heartily recommend them. I have owned these before and always found them round too. 60k guarantee also.
Jim Smith