Handling performance: most important chassis bracing/reinforcement - per application?

This might be a good resource to collaborate on for this particular forum...but I'll need your help because I don't have enough first hand experience to say for sure what is needed. My guesses could end up wasting peoples' money. :)

This is what I'm thinking: For each application, which chassis reinforcements do you see as the most valuable? Which ones are absolutely critical? Perhaps list the type of bracing and what it accomplishes?

These are some suggested categories, feel free to create your own:

Thanks for any input at all.

Improved street driving:
Basic improvements to responsiveness and feel


Aggressive Street driving:
Improved handling limits/more predictable at limits


Autocross:
All of the above plus improved durability


Track Day/Road Course:
All of the above plus safety

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Straight line guys may have different priorities?


Street/strip-
Able to withstand repeated stresses from increased engine power/hard launches

Drag car-
Street/strip plus safety