I have never had the back end kick out unpredictably or uncontrollably, with much driving near (or occasionaly above) the "limit" on both twisty canyon roads and race tracks.

The closest I came to "loosing the rear end" was after out-braking a car coming off a long straight, I was way off line and blew the apex of the 180 degree turn badly. I dropped a wheel into the inside dirt, and when it popped back out I was sliding the rear. I just stayed on the throttle and counter-steered, and power-slided through the corner and back on line. Driver error, not bad behaviour of the S2000! Kind of fun, but could have been a real mess if things hadn't worked out.

I should say that I run the Mugen sway bar and Spoon X-brace, as well as a recent semi-aggressive alignment. I believe all three of these things really help at-limit handling, especially on a track.

 

Once you get used to it, slidin' it is almost half the fun!!!

 

Actually, this is the opposite of my experience! I agree they grip like stink, but will complain loudly long before they slide, and break away gradually. One reason I've hesitated going to race tires is that I've heard they DO exhibit the binary slide characteristic you describe...

 

I know I don't get much play on this idea on this board, but I'd suggest you try some other high performace tires to see the difference. Of course, it's just my opinion on my car with my driving skills...

 

The key to driving the S2k at the limit is smoothness. The steering is so quick than any excessively quick imput can bring the rear out. Lifting in a turn, heck even a very slow shift when you are accelerating can cause a step out of the rear.
These are the normal mechanics of a rear wheel drive car setp up for minimal understeer. A change in sway bar diameters would be much more effective than changing tires if you are looking for more understeer and less oversteer (in otherwords an easier car to drive and push to the limit)