Mercedes versus BMW

I'm not in the same league as you guys regarding devotion to peformance and so on, but I thought maybe you would be willing to help me find a car that handles better than the standard E320. My wife has a 1994 E320, and it's a good car, but doesn't compare to, for example, a BMW 528i for handling. It has standard tires and wheels, etc. I am looking for a car for myself, and want Mercedes quality but BMW handling (so to speak). I hope this will raise a hue and cry from some of you who are convinced that Mercedes can be as good or better than BMW, and will point me in the right direction. My budget is around $20,000.

Thanks