Okay, so you are running the medium setting..
INCLUDES: Two Silver (soft) springs 72215a.
One black (medium) spring 72215b.
One Gold (hard) spring 72215c.
Four black spacers 72215d
One grease tube Z160
One instruction sheet.
But of course, it really depends on the size of the diff housing.. the gold spring might simply be too stiff if the diff housing is smaller on the Kyosho then the HPI, for example...
Still, I want to give the 100k diff fluid a try, though.. ha ha ha!!
I used the black one