b18c with i/h/e pro series intake manifold and chipped ecu

Been searching and im not finding much.Im wanting to get a new throttle body n if i port matched my intake manifold wouldnt that be 68mm? And i dont want to go to big cause i read where you could lose torque, im wanting to build my head eventually just buying the supporting mods first.
Wondering what size of throttle body to go with ?

Any help would be great thanks in advance