My take on this is:

On a nasp motor the engine is affectively a pump which sucks in the air.

The bigger the pump, (cc) the more air in theory it can suck in and more power it can generate which is why big V8's have big power.

On a turbo motor the air is forced fed in so the only limiting factor as stated above is the head flow.

I've destroked my engine to reduce torque low down and increase revs which will hopefully make me more power higher up the rev range which is better suited for my type of car.