I hope this info. helps in some way. I run a Yokomo GT4 and the springs can be used front or rear. The following is the spec. chart for them.
AFM
YOKOMO GT4 SUSPENSION SPRING DATA
COLOR WIRE OD COILS LGHT EXTDIA INTDIA LBS/IN
Brown 1.70 5.00 22.15 17.55 14.10 32.99
Grey 1.70 5.50 22.15 17.55 14.10 26.55
Silver 1.70 6.00 22.15 17.55 14.10 23.87
Green 1.60 5.00 22.15 17.55 14.10 23.54
Yellow 1.60 5.50 22.15 17.55 14.10 23.20
Red 1.60 6.00 22.15 17.55 14.10 18.93
Drk Green 1.50 6.00 22.15 17.55 14.10 16.83
All measurements in mm except pound rating.