While the RX 400h comes standard with Goodyear RSA tires, it is best to negotiate for Michelin Energy MXV4 S8, b/c of ride improvement, superior wear, better gas mileage by 5% or more. Michelin Energy on the RX make a big positive difference in ride quality and quietness. Don't bother with the Mark Levinson stereo; but do opt for the built-in GPS with Bluetooth and rear view camera. Acceleration at all speeds is impressive; w/a light foot, gas mileage can be 29 mpg+ in city and on a good day 27 mpg+ on the highway w/cruise control active. Expect 25 mpg+ avg. Very nice set of wheels.
Wood trim mixed with the brushed metal finish on the inside lends to a classy interior. Ride quality in 2008 has improved over the 2006 RX 400h. Blue interior courtesy lights add a neat touch.
Sound insulation could be improved especially around the doors - while road noise is not overly intrusive, the RX 400h is not as quiet as an Avalon, e.g. Buttons for heated seats could be bigger. Slight rattles from plastic-on-plastic can still exist, but seem to have improved from 2006.