From my understanding those "boxes" were originally just a resistor that intercepts and reduces the voltage signal to your ecu (i think the airflow signal)... Tricking the ECU to raise the fuel ratio per stroke... Those things are getting bigger and bigger (as in the black box). I remember this mod back when I had my DSM...

A total waste of money... considering a resistor alone is like .89 cents or something... ooh dont forget the couple thousand to replaced your blown motor!!!