Glen,
The E500 springs work well for the most part. While the fronts can be mated with 500 shocks, the rears have to be used with the original shocks. This makes the damping a little more abrupt than I would like. The car is also highly sensitive to tyre choice. If you have less than perfect roads, as we do in Philly, you'd be well advised to throw on some Pilot HX MXM4s in H rating (used 215/55-16). When I tried Pilot Primacys in the same size, handling and braking improved visibily over the HXs, but the ride depreciated substantially.
The car is no BMW sport wagon, however, handles pretty darn well while being baby comfortable.