Just this one:



A boost gauge is nice but keep in mind that most are calibrated for 25-30 psi. As you're only running 5 the needle will hardly move. Just make sure it's one that shows vacuum.

Other gauges like oil temp and pressure would be nice if you track of drive hard.

 

yeah i didnt think about the 5 psi most boost gauges register at around 10

 

A.) AEM Air-Fuel Wideband - to make sure you don't blow up the engine from being too rich or lean

and either

B.) Defi BF Boost - to make sure the SC belts or vacuum line don't loosen and I lose boost (belt) over time or worse (vacuum)

C.) Defi Oil Pressure - to make sure no leaks develop


My SOS pillar Pod only had room for 2 so I chose A & B.

Links to gauges below in my sig.