It's a good tool for boost measurement if you aren't going to mess with the MAP with a boost cut defender or other type of MAP clamp. It's accurate and you can datalog with it, along with being able to see your actual AFRs, boost intake temps, etc. Once you put a boost cut defender on or install a MAP clamp it will not read accurately anymore because it only displays what the ECU is seeing, and a MAP clamp is designed to fool the ECU into thinking you're running less boost than you are.