rb20 to s13 Wiring Confusion

[Jetskieng]

First let me start off and say yes i have read all the wiring guides and what not... but i still have some confusion and would like some clarification from people who have does this.
Ive check carl H and the rb20 wiring guide for dummies and a bunch more...

1.) Since im using the lower harness from a ka (DOHC) do i need the 8 wire plug or not? and what exactly am i switching on it to make it usable? ...Ive read other posts and some say I dont but i want to be 100% sure. Also what is the 8 wire plug for again??

2.) I read somewhere on a different post about these guides not covering a cold start wire and a IACV wire? can anyone explain a little bit more on this other then it goes to pinout 43...

3.) I am just confused on how to wire the whole thing up for now..so if someone would like to help me out or take a further step into explaining the whole procedure, Id be extremely greatful!

Thanks