[ScottyS]

I've been playing with this issue myself, as I have what probably qualifies as a very non-stock setup, but I did not build it to race either.

First: Buy the best gauges you can afford, the Defi setup sounds awesome, I wish I had started there (I should have applied my rifle optics philosophy to that lol). Some quick research on the Prosports shows a LOT of bad experiences.

Which ones: For my application (commuting/street driving with a non-stock unique setup), I find the single most useful gauge so far to be Wideband AFR. I would say get Vac/Boost, Wideband, and EGT all at the same time. Then add Oil Pressure and Oil Temp later.