Spring is meant to hold the weight. Strut/Shock is meant to control bump and rebound.

All hydraulic shock absorbers work by the principle of converting kinetic energy (movement) into thermic energy (heat). For that purpose, fluid in the shock absorber is forced to flow through restricted outlets and valve systems, thus generating hydraulic resistance.

Stiffer springs mean more and quicker transition from bump to rebound. Also have less suspension travel so if shock valving or internal friction cause too much heat you blow. I'm not saying this is the case for AGX of Tokico w/Skunks cuz I don't have that setup. I do know that my Koni's have been bulletproof.

Adjustability is good for me. I adjust my yellows a minimum of twice per year, usually much more depending on how often I get to autocross.