When I mentioned: "...harder to operate..." it was meant not neccesarily physically harder, but less controlable. Most of these disc linings are of a harder type substance than street discs, this allows for rapid, abrupt on/off gear changes. Racing clutches don't tolerate much of the slip that's done while street driving (letting clutch out slowly for smooth, gradual take-offs from a stop).
As for different pressure plates with harder springs, pedal effort can be decreased by installing (an aftermarket) SMALLER I.D. clutch master cylinder (yes, going smaller actually increases output effort. Trick used by racers to help change bias on dual-cylinder braking systems).