Personally I'm with you jecey, I believe that for the street a system like PSM is essential if you want to enjoy the car fully in the street, it hardly limits you on the street and even on the track, with its semi-OFF mode. And the advantages are obvious, it won't defy phisics but its sure proven to reduce accidents, and no matter how good you are of a driver you can always misinterpret thye grip at a curve, or be surprised by an obsticle or another driver's manuever, or simply make a mistake as well all do. It doesn't have anything to do with good or bad driver. This can happen to anyone like I said before, wether you are a profesional racecar driver or a normal driver like me.
A personaly story about this.
A couple of years I almost lost it once coming out of a left curve coming out wide open throttle in third gear in the rain. Going out on a weekend trip on what is regarded as one of the most dangerous highways parts of europe due to its curves and the number of accidents there.
I was overtaking cars in the left lane driving spiritedly enjoying the car in the rain, and a car (at much lower speed than I) from the right lane jumps without looking or signalling into my lane and blocked my lane, my exit of the curve (I was hard acceleration out of the corner in 3rd gear so at about 100-150km/h) and had to suddently lift the throttle in the bend under the rain knowing what that would do the rear of the 911 in such circumstances, or otherwise collide against his rear and get trapped in a chain of accidents by the other cars on the road. So sure enough the car went into oversteer so I tried instinctivley to control it and PSM jumped in to help, and the car came into control fortunately. I walked away from it with just a scare and a reprimand from my wife (passenger) for driving that fast in the rain allowing little room for maneuvering in case something comes up like that car jumping in front (she is right but its in my nature).
I don't think I may have been able to control it at that speed under the rain with so little room without the help of PSM, I don't know, but I'm glad its there, if it were a GT3 I may not be. Before I had it I never missed electronic stability systems in my previous cars, but nowadays I will never buy a car without electronic stability controls, its something you don't realise you need or its advantage until its too late