You need a lot of power to make boost with a blower. (the system shown there can't be described as a turbo, since its not driven by the exhaust, so its just a blower, albeit electric)
For an example, the blower on the Ford GT uses 100HP at redline. (Note the super wide 7 groove belt to transfer the huge amount of power from the crank that the blower requires)
An electric blower for a Viper would need a huge, very heavy electric motor to make any really signifigant gains. Thats why with this little system that they show there in that ad, they are only talking about relatively small PSI of what was it, 1.5 PSI on a 5.7 liter? Any boost is better than no boost at all, but if you put a blower on your car, you don't wanna have to tell your buddies that it only adds a few horsepower! But if you don't mind its humble aid, then its just a matter of hp per dollar. (But keep your hood closed to avoid creating ripples of laughter!)
I experimented with electric blowers of my own design on a Dodge Dakota V6, and my old 1989 Vette. It was much more effective on the Dakota's smaller V6, with its smaller CFM requirements. I learned a lot about blowers through this process. One advantage is that you can put them almost anywhere, like inside bumper cavities, any nook or cranny where they will fit. You couldn't detect mine on my Vette, it was totally invisible, even with the hood open. You don't need to touch the exhaust, nor mess with the crank pulley. If it weren't for the input power limitations, I'd still be interested.