There seems to be a pletora of these bolt on(or wire in) boxes around at the moment, I have only seen one so far allegedly for a TDCi Focus, customer had bought off e-bay, instructions were dubious to say the least so I refused to fit, seems as though most of these tap into the fuel pressure regulating circuit confusing the ECU to provide more fuel across the range , these can range from £50 up to several hundred pounds ,seen more bad press on these than good so be careful !