Granted I have no experience with H&R ....but according to Italian Abarth forum they are generally considered stiffer than the Pro Kit (which I do have on my car)
I am very happy with the Pro Kit.... far less bouncy that the standard NP springs
Been running them since May and they've bedded in nicely. Certainly softer under normal driving than the std springs, as you say less boucy, jiggly. Quite progressive so much reduced body roll, more compliant over rough surfaces, but come into their own when cornering hard.
Certainly no need to change the dampers with these, they work well together.