Voodoo box is an injector pulse width modifier box that'll give you some extra fueling for use with stock ECU/injectors. It'll give you enough fuel for about 5-8psi, depending on what type of turbocharger/supercharger you're using as well as the rest of your setup.

Flyin' Miata sells the Voodoo Box, BRP sells the very similar Powercard as well as the far less similar Elf (the most expensive and feature-rich of these injector pulse modifying devices...the Elf actually has the ability to drive extra injectors in addition to the stock ones).