I love my Innovate LM-2. I bought it off ebay for alittle under $300 new and got an input cable to input RPM for another $20. It data logs to an SD card and comes with software to analyze it on the computer. It pays to have a datalogger so you are not limited to watching the gauge down the track. Most gauges don't update fast enough to find smaller problems but if its recorded you can track things down much easier. It can also read OBD2 live data with a change of a cable and read DTC's(I think).