Couldn't agree more. Those are the two things that have a tendancy to change without notice. Once your fuel and timing is set, AF and EGT shouldn't fluxuate too much. But boost leaks and oil leaks are things that can just pop up.

 

since we are on the topic of gauges, what TWO would you get for a supercharger? or do you think it's nesccesary?

 

Well Boost=RPM (sort of), so probably not boost.
Maybe Oil Pressure and AFR? But then again if you're tuned, AFR should be okay.

 

I'd get both the same for both SC or turbo. Boost is boost after all