[DaveG28]

I was told they are between Tamiya yellow and blue, but haven't checked.

In terms of using them, to myself they certainly didn't seem stiffer than the Tamiya blue, from the handling to me they felt mildly stiffer than Tamiya yellow, but compensated by feeling slightly "better" (hard to explain) than the Tamiya yellow, maybe more consistent, which may be due to either the fact the Tamiya spring is cut (which I don't like) or, from memory, I think the Kyosho spring has more coils, maybe that helps the "feel"!?