The ram pipes in this exercise are to increase air flow into the carburattor, once it is in the carburettor, it doesn't matter if the characteristics are the same as before, because more air means more torque, if further increases in efficiency within the rest of the system are available then in theory more power will also be available.
Actually the harder the engine has to suck, the more torque will be produced............
Sort of right, try putting a bung in your carburettor to how much torque is produced ?
An engine that is wide open, ie no restrictions will still produce torque, the reason why an engine will produce torque is down to the type of airflow, there are benefits from laminar flow, laminar flow is often increases as the amount of vacuum increases, however there are limits, with a Vena Contracta as the "suck" increases the Vena contracta decreases, ie less air amounting to less torque