Does anyone know the spring rate of Eibach Prokit for IS250? and for the IS350?
I searched at eibach website but found nothing.

For comparison, Tein S-Tech spring rate is:

6.5 kgf/mm or 364 lbs/in Front
6.8 kgf/mm or 381 lbs/in Rear

and F-Sport spring rate is:

6.7 kgf/mm Front
7.0 kgf/mm Rear

Question:
1. Is it true that the higher the spring rate, the firmer and harsher the ride?

2. Spring rate for Eibach Prokit 250 and 350?

 

springs experts where are you?

 

Question 1 - Yes, it is true.