In order to tune your vehicle, you need the have the proper gauges.

The most important "tuning" gauges are the boost, Exhaust Gas Temperature (EGT), Air/Fuel, and Oil Temp/pressure.

The boost gauge allows you to fine tune and VERIFY the boost level on your car?increasing or decreasing boost levels according to the amout of modifications you have on the car.

There are typically two types of gauges?Mechanical and Electronic. Electronic gauges add features like warning lights, max reading, etc.

The EGT and oil temp gauges help you monitor the health of the engine. If things are not going right, they will let you know. For example, if your EGT is too high, typically it indicates that you are running the engine too lean (if you have an Air/Fuel gauge installed, you will be able to verify this). For optimal power EGT should read 700-850 degrees Celsius (depending on modifications and sensor location).

The Air/Fuel gauges is a particularly helpful gauge (though not as common as boost, EGT, Oil Temp) that allow you to monitor whether the engine is running too lean (possible detonation) or too rich. If the engine is running too rich (obviously better than running too lean...but still not good) you are loosing power and wasting fuel.