Electronic devices consisting of hardware and software for downloading and uploading information, files and data to and from land vehicles and trucks for increasing or adjusting engine performance, horsepower, and for engine diagnostics; handheld and mountable electronic devices with displays for use in connection with land vehicles and trucks to assess, monitor and record engine performance, horsepower, and engine diagnostics; downloadable electronic publications in the nature of text files and electronic manuals for use by professional and amateur auto mechanics in the installation, maintenance and troubleshooting of the foregoing electronic devices; downloadable operating system software updates for handheld and mountable electronic devices with displays for use in connection with land vehicles and trucks to assess, monitor and record engine performance, horsepower, and engine diagnostics; gauges for land vehicles and trucks, namely, automotive gauges in the nature of water temperature gauges, boost gauges, vacuum gauges, and exhaust gas temperature gauges