These two blokes that have a car mod TV show in AUS tested the eBay electric "superchargers" and discovered how to effectively add twin boost to your car that actually increases power! So you can forget about expensive intercoolers and blow-off valves...

They need gas powered blowers if they want to go farther than the Dyno machine. :bulb:

even the $300 eBay purpose-built "supercharger" (a tube with a fan inside) couldn't do what those cheap leaf blowers could do. This is original video:

Actually, I think they look more like overgrown blow-dryers.

BTW- they didn't use a blow-off valve in their setup, even though you could put one on any kind of engine- but that's another how-to video by these guys. Refer to this video: