I was friends with an IEI girl and she was also a 4 core like me, maybe a 1 core. On the surface we both were quiet but she seemed more aware in my opinion of se. She also seemed colder and more mysterious than me, I came off a bit more friendly and absent minded. I agree her fe seemed darker and she almost gave me this evil vibe not that she was gonna do anything really harmful though. She had this mean streak though and sometimes would get mad at others. She also stood strongly and would stare at you like she's analyzing you.