Newb to Nissan

My friend is a Nissan freak, and I get really confused when he talks.
We're only talking Nissan sports cars here. I know there is a 300zx, 240sx, and 200sx, or 180sx, but then there there is s13, s14, s15, Silvias. I'm not sure what is what... could someone please help me.

240sx-
s13- 89-94 240sx the hb is called a 180sx in japan, it also has a sr20det
s14- 95-96 240sx
s14 koukie- 96-97 240
s15- 98 and on silvia

all 240sx's are silvias, just the american counterpart, and they dont have a sr20det, they have a ka24d(e)

Thanx a lot