 Traded in my 2005 Porsche Cayenne s for new x5 35i. Test drove x5 35d but felt the gas version was more refined and still got decent mileage, though the diesel had great torque. It is very smooth and ride quality is great. Firm ride and it's very luxurious. Cayenne had much better handling, cornering and shorter turning circle. New 8 speed automatic transmission is very smooth but doesn't really downshift like my Infiniti and Porsche. 