This^ is correct. Intercooler keeps IAT's from the compressor in check prior to entering the combustion chamber. Cooler denser intake temps, aids in producing more power ie, tq and hp.
Keeping IAT's down as close to ambient temp is the goal. This is why during the fall and winter the engine will produce more power overall. When you adjust the VE, Fuel & Timing maps to take advantage of reduced temps, it will produce more tq and hp.
It's a combination off all three that makes the difference (Intake, Exhaust & Tuning). You're simply optimising/maximizing what's available. However, everything has it's part.
Dynamometer is a measuring tool and readings are relative to; ambient condition, altitude, type, calibrations, mechanical age, data acquisition, etc. It's not even a true demonstration, of how the engine will respond on the road. Keeping this in mind, it's easier to understand why, every dynamometer produces different results. How the engine responds on one will not be the same on another.