Having driven rear wheel drive most of my life, I have become quite use to all the shortcomings of that configuration. In the early days the cars had coil springs on the front and cart springs on the back, the dampers were always on the limit when the cars were driven fast. It was not until I bought our first Z3 that I could honestly say, here is a car that has been properly designed. Both of the Zed 3s I was fortunate to own had different handling characteristics. I am very lucky in that I have always had the ability to drive any car and adapt quickly to its individual characteristics. Both Zed 3s were what I would call proper drivers cars. When I bought the Zed 4 I felt here again was a step forward in its ability to be driven hard round a corner and feel safe at all time. You know, you get a sixth sense about a car and you know instinctively when it's reached the end of its chassis ability. As some may know I have had some misgivings about the E89. As TT says it's more an SLK than a true sports car. However as hard as I've driven mine, I have never yet reached the limitation of it's Chassis.
I can see the advantage of a strut brace on a track when under heavy braking and then powering through a corner you feel how unsettled the car is, you want the car to corner flatly and you feel every millimetre of role as you exit the corner. Intuitively You want harder springs and lower suspension. But on the road those things are not so important, our roads are too uneven for hard suspension to be comfortable on long journeys.
You need a compromise, and that's what a stock Zed gives you. So summing up I would say you pays your money and takes your choice. The Zed, whatever Zed will serve you very well as it came from the factory, If you take it on the track, now thats a whole new environment, and the zed will need a few tweeks.
Mike
PS sorry for War and Peace.