I'm planning on getting a boost gauge and am thinking if I should also get an afr and oil temp gauge . Is the functionality of those 2 worth it? I know boost gauge is crucial if you have a tune.

 

Air/Fuel is also crucial but not just the pretty one with the lights that dance back and forth with out any purpose they basicly let you know your O2 sensor works, what you really want to invest in is a wideband air fuel unit/gauge. There are a few out there I personally have the Zeitronix which contains both the air fuel and boost as well as egt, and is all easy to log with a laptop, and you can wire it to your ecu for additional things to monitor within the same program. Hope this helps your decision.