Ninja 500 is softest of all shocks! It has 300-lb/in spring.
Even softer than ‘88-07 pregen’s 440-lb/in spring.
Softer than ‘08-12 pregen’s 475/lb/in spring. I think RaceTech’s claim of 520 is wrong.
Softer than 300’s 475-lb/in, same as new-gen.
Check out
www.ex-500.com and see that most common rear-shock upgrade on 500 is going to new-gen 250 or 300 shock. New-gen 250 shock is actually quite stiff, what you may be looking for is adjustable damping.