ram air applies to any vehilce that can travel fast enough.
But motorbikes only really use it since they can achieve ridiculous speeds needed to create a tiny amount of positive pressure, not even near a singel PSI as you have to be doing well over 200mph since the max theoretical pressure you can achieve at 200mph is about 0.7psi.
Anyway, you need to design an induction system primarily for he use of ram air if your going to use it, and you need a HUGE plenum area and a relatively small intake to create a pressure drop.
The reason the intake is remotely located is to get it away from the hot engine bay where air temps are around the 70-80 deg range and you can lower it by 50% easily by using air from outside the engine bay.
Then you get into reduced temps, increased desity, more O2 to burn, more power so on and on.