I was amazed at how thick and heavy the stock bar is,
heavier than any aftermarket bar I've ever seen,
and yet the car likes an even stiffer bar, this monstrous
comptech adjustable bar. That seems a little odd as far as
suspension tuning goes, like that variable has already
been tweaked to the max by Honda to get the rear end under control.

I've done some test runs with the bar set to 97% stiffer than stock
(fourth hole). The car feels really sweet in an 'S' turn, very solid, a definite
improvement.
It also gained a few more mph in cornering speed, but there's still some odd behavior.
You feel like you are in a steady cornering state,
constant throttle, speed, then the tail sort of shifts in a different direction.
Actually it feels like snap understeer, then oversteer, which
is a pretty weird sensation because your brain says
"Hey, there's no such thing as snap understeer!"
Downhill corners don't seem to do this.
It has been suggested that the rear springs are too soft and fully compressed
on an uphill corner they can perhaps pogo off the bump stop
on one side if there's the slightest roughness in the pavement.
That might explain what's going on.

I'm switching to Toyo RA-1s next week, but I don't think
that's going to settle the rear suspension. Guess I'll try
some stiffer springs and shocks.

MG

 

I have been running my swaybar and full stiff (Street and autox) with the front shocks (Koni yellows) set on full stiff also. The rear I have left on full soft. With this combo, the car has been reacting very well. I get a slight push sometimes, but I can control it with the throttle. It reminds me of driving my Miata. I have not experienced the weird handling that you have.

 

I had koni yellows on my NSX with eibach springs.
They worked well but I'm a little reluctant to use them again because
their performance deteriorated after about 30k miles, making the car
bob at high speed no matter how stiff I adjusted them.
Ultimately I had to get another set.
Sort of a hassle doing suspension mods twice,
though I probably won't put that many miles on the S2K.

MG

 

I have not heard that about the Koni's. That is good to know. Installing the back shocks was a MAJOR PITA. Well, the driver side anyway.

I put about 30,000 miles a year on this car, so I hope they don't give up after a year.

How do you compare the NSX to the S2000?

 

The NSX was better at high speeds than the S2K,
cloverleaf cornering, highway cruising.
The S2K is better at low speeds,
feels lighter and more nimble in tight turns.
The racecar vs gocart thing.
I'd much rather drive narrow backroads in an S2K.
The NSX was really made for the highway
(particularly the 91 coupe without the power steering).
The cars overlap in some areas of their performance envelopes
but don't compete with each other.

MG

 

All shocks will show wear, depending upon use and springs it can be fast or slow. Another brand would not likely be substantially better, and at least the Koni's can been sent in for a rebuild.