should be free.99 under warranty
I run a Koni Yellow/GC setup on my ITR (350/400) GC is definatley the way to go.
One thing that is great is if you purchase the same height of springs, you can swap the rates from front to rear.
For example, I went from autox'ing a 97 Prelude to a 97 ITR... The R was much more responsive and snappy, so in order to adjust I ran the 400 rate up front and the 350 in rear, to prevent oversteer or spinning
After more seat time, I have switched the heavier rate to the rear and the car rotates very, very well.
The rates you are considering are right in the ballpark.. 500-600 in is the maximum rate an OTS yellow can handle. Anything higher than that, general consensus is to revalve.
Some other things to consider is the actual curb weight of your car (you may not need as high of rates as you think), and the frequency it will see the track vs. the daily driver aspect.
I live in UT as well.. We should meet up and you can drive the R and see if you like how it feels.
Ill be in Wendover this weekend for IVR, if you will be out there you can take a ride in the R
