if I recall correctly, dampers (aka shocks) only dampen the oscilations. Stiffness comes from springs.
In other words, if your springs are fine and of the same stiffness as the ones that you wanna get as a replacement, there wont be any difference in how firm the ride is.
In order to answer your question, you need to know if those new springs in new struts are any different mechanically from the once you wanna replace...
