Nick,
I autocrossed my GSR in STS with the Koni's and I was very happy with them. I was able to dial the amount of over/understeer that I wanted. The ITR that I have also have them, so I'm expecting good results next year.

Regarding the rear's on the Type R, they are adjustable, but you need to remove them from the car and twist the two halves relative to each other. I don't know why Koni did this, but they did. The GSR had adjusters at the top all around.
NOTE...The rear's are set for 3/4 firm all the time, and I'll set the fronts to full firm for autocross (via the top adjusters).

I've also heard of someone that has double adjustable Koni's on a Type R. I don't know if these are readily available or if they had Koni modify them.

It's my understanding that most of the top solo ITR's run the Koni struts.

I hope this helps.