err no? They're selling a standard nose drive with a smaller pulley.
Q: What is the difference between the Magnuson Nose Drive and the Pulley Boys pulley?
A: There are two main differences. First, the installation time on the Magnuson Nose Drive is much longer than the Pulley Boys pulley because the supercharger needs to be removed for proper installation. With the Pulley Boys pulley and pulley installation tool, the process can be done on a car without removing the supercharger. Second, with the Magnuson Nose Drive you get the advantage of being able to easily swap pulleys on the nose drive since it is a keyed drive. With the Pulley Boys pulley, you must go through the same installation process again if you wish to change sizes. For most people, one size change is all they'll ever do, so either solution works out to be the same. They both yield exactly the same power gains for the same size pulley.
Honesty in advertising, gotta be a first.
Stuff got done.