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See Tugly's post (#7) above. Basically the while point of the boost gauge isn't to protect the engine from too much air, it's to protect the turbo, and to see what the turbo is doing. The stock turbo is rated for 30 psi max, but that's 30 psi coming directly out of the turbo, not 30 psi going to the engine (there is a drop through the intercooler). That's why the hot side is recommended.
If you're like me and just want to monitor what's going on while towing and see what's going on in different tunes under different situations, but never quite hitting 30, then the delete plug is a good option.
To back up jeffreyt's statement, this is what my gauge read with stock injectors and stock turbo with a DP Tuner:
Before I could get some bigger sticks, I was thinking of that line from "Jaws"... "We're gunna need a bigger boat".