Another OBD II gauge from PLX Devices [(408) 745-7591; www.plxdevices.com] is the DM-200 Intelligent Multifunction Display. It allows you to display up to 50 different parameters, including rpm, boost, fuel pressure, air flow, fuel trim, error codes, and much more. PLX also offers a wideband air/fuel gauge, a datalogger, and other gear.