You shouldn't need the adapter kit with a supercharger; only if you don't have holes for the brace from the factory.
For some reason, the ZL1 has a hump in the brace. I have a Maggie and the standard brace fits just fine.
Originally Posted by Deftones
The adapter kit requires drilling so why not drill and bolt the brace right on?
The shape of the tower is different on the ones that come drilled for the brace. The adapter kit makes up for the lack of relief for the brace: