If I remember correctly, the KB supercharger was bolted down to a large alluminum plate, the IC was bolted to the bottom of that plate, and then the whole thing was bolted to the lower intake manifold, and that assembly was bolted to the heads. I'm not sure what the lightning/cobra has for comparison.
See pictures of my install here:
http://www.ncma.ca/forum/viewtopic.php?f=3&t=524