I have no idea about the supercharger but I would recommend some MeisterR Europa coilovers as by the time you have imported some springs, decided to fit new shocks and top mounts as well :winky: you might as well just fit coilovers!
Mine have 12kg front springs and 8kg rear springs that came as standard, I am currently running 2 clicks from the softest damping setting on the front and 1 click on the back and it rides as good as if not better than any car I have lowered on just springs :)
Andy