i did this swap twice before, i know everything about the S14B20 of the 320is
1- you must install the 265 tranny of the 320is, it's a dogleg, fun to drive, best performance with the engine, the engine will never bolt on to any other transmissions unless they suite the M10, any tranny that fits the M4X series will not fit at all.
2- get the 3:46 LSD diff
3- the radiator will not work, you need the S14 one
4- the electrical work is simply plug and play, you will only need to get the 8000 rpm of the S14, it also has an oil temp sensor that is very important.
5- the engine runs on RON 98 octane only, anything less will kill it, i got a couple of destroyed pistons at home, i know what I'm talking about, this engine does not have knock sensors.
6- get the stock air filter and don't go the cone filter route, also the AFM is not a restriction at all, you will understand when you drive it.
Cheers