Trust that this one works, knight builds wicked forced induction kits, they made Turbo and SC kits for the scort back when I had one. Thomas Knight knows his stuff.
Keep in mind, he just sells the supercharger, it'll bolt up, but you still need to worry about fuel enrichment, tuning, etc. Just like any FI kit.
My only concern is that this thing must pull a wicked amount of juice to run, more than a starter motor. They in fact say you need a battery bank (of a couple mil-spec batteries weighing 13 Lbs each) soley for this unit, and it acts like an electric nitrous kit (15 sec. bursts at WOT)
You may notice that it's a roots-type supercharger, driven by three, very large motors, the fact that the compressor housing is so small compared to, say, a TRD
supercharger, it probably won't put out as much boost. But WOT operation makes fuel enrichment not as big an issue. It's good for 32 HP on a V6, Probably good for 25 or so for a 4-cyl application: I would definitely like to see more dynos of this thing on other engines..