C4 Advice from a C3 Owner

Hi all...
I have a question for ya. Does anyone know of a early model C4 owner that has put a composite rear spring in their Vette and if it made any improvement? I myself own a C3 and I love my new composite spring. I have a friend that has an '84 Vette that would like to improve the ride. My father and I offered to do the work of installing a new spring and shocks (since this friend isn't good with a wrench).

Does anyone know if this is a more or less difficult job for the C4 verses the C3?

Thanks for you help.