They do they just don't relise it the breather that connect to the efi pipe feeds fresh filtered air into the engine the one connected to the manifold draws that air in, it does this to stop the engine from sweating constant heating and cooling causes moisture the standard system is constantly drawing that moisture out, the way people plumb there catch cans up so both lines go to the can is basically doing nothing but building the moisture up in the engine. it's not even catching the oil that would technically be drawn into the engine so basically useless or just bling causing problems