there are like 11 sets of springs to chose from:
#308393 Super Soft YELLOW (D = 1.4) (14 lb)
#308384 BLUE-GREEN (D = 1.5) (15 lb)
#308394 Soft WHITE (D = 1.5) (17.5 lb)
#308385 LIGHT-BLUE (D = 1.6) (20 lb)
#308395 Soft medium BLUE (D = 1.6) (22.5 lb)
#308386 DARK BLUE (D = 1.7) (25 lb)
#308396 Medium VIOLET (D = 1.7) (28 lb)
#308387 LIGHT-PURPLE (D = 1.
(30 lb)
#308397 Medium Hard PURPLE (D = 1.
(33 lb)
#308388 LIGHT RED (D = 1.9) (35 lb)
#308398 Hard RED
+ silver and gold/copper (kit springs)
And you won't need them all.
I would take the yellow, blue green, white, and maybe the light blue.
That's all you may ever need for rubber racing.