JDM GT Rev.A
Original GT setup. Great balance of performance and ride comfort. I currently use this setup as my winter suspension. It is firmer, but not too firm. Closer to JDM SpecB Rev.B than to JDM GT Rev.C (had both setups earleir). Everyone who has this setup seems to praise it, especially with Pinks.
Part numbers: 20310AG060 (front right), 20310AG070 (front left), 20365AG040 (rear)
JDM GT Rev.B
This one is bit of a mystery. Does not really feel softer than JDM GT Rev.A. Interestingly rear shocks are the same as on JDM SpecB Rev.B, front struts are different. I just drove a car with these on Pinks and indeed the setup seemed more complaint than JDM SpecB Rev.B, but the difference is not big. Note, there is an old post quoting someone from Bilstein Japan saying this setup is for SpecB and tuned for 18 inch wheels - that is incorrect, I verified this against JDM parts database.
Part numbers: 20310AG140 (front right), 20310AG150 (front left), 20365AG120 (rear)
JDM GT Rev.C
This is the current JDM GT and JDM 3.0R setup, present on Rev.D cars as well. Also used on 2006-2007 USDM SpecB (not sure about 2008 yet). These are noticeably softer than any other revisions. Give nice and controlled and oscillation free ride, but they are more on the comfort than performance side. There were complaints that these do not handle stiffer springs (Pinks) very well and feel bit underdampened. I can believe this as in certain high speed situations these did not feel as secure as other revisions.
Part numbers: 20310AG400 (front right), 20310AG410 (front left), 20365AG260 (rear)
JDM SpecB Rev.A
The original SpecB setup, stiffest of the bunch. I rode in a car with supposedly this revision (not 100% sure, not confirmed by part numbers) - it felt marginally stiffer than SpecB Rev.B. Opinions about this setup range from "great ride" to "too stiff for daily driver". I guess this is very subjective plus it depends on the road conditions, wheel size, tires, etc.
Part numbers: 20310AG100 (front right), 20310AG110 (front left), 20365AG050 (rear)
JDM SpecB Rev.B
Supposedly softer than Rev.A. I had it on my car with Pinks for few months and liked it very much. Excellent performance, yet still great ride. However, can be too harsh on really bad roads if paired with stiff tires like RE070.
Part numbers: 20310AG180 (front right), 20310AG190 (front left), 20365AG120 (rear)
JDM SpecB Rev.C
This is the current JDM 2.0 SpecB and JDM 3.0R SpecB, present on Rev.C cars. Bit less aggressive than Rev.B, yet still excellent handling and great ride. This is my favorite Bilstein setup so far for a street car - I think they really got this one "perfect".
Part numbers: 20310AG420 (front right), 20310AG430 (front left), 20365AG270 (rear)