1) yup. s13 and s14 have knock sensor. pluggher eeeiinn!!!
2) goes to egr or iacv. i blocked both mine off so i dont remember where that plug went to. it should be a big grey plug kinda like the tps, but goes under to back of plenum. if u have egr blockoff and its for egr, cap the wires. if that plug is supposed to go to iacv, goodluck. use fsm.
http://www.zeroyon.com
3) u ditch ur A/C? these go to the metal cone canister thing down by the framerail. (i ditched mine too)
4) from left to right: ignitor, ground, coil, power steering fluid level sensor. i cut my pwr str sensor off.