I've been reading about manual boost controllers and I have a few questions.

First of all, what real gains can I expect from implementing one of these on a 300D, and if I do how high can I safely adjust the boost without other modification?

If this is all I plan to do, is an EGT gauge in addition to the boost gauge a necessity?

And, Is there any point in doing this with the stock turbo?

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1984 300CD