Keth,
The only thing I would add to what has been said is that, if you use your SUs from the B18, you'll probably want to change the needles to KD or DX to get the best out of the B20-- RR has also been recommended here. Check what is in there now. Probably ZH. As for routing the vent hoses: I did mine block breather/oil trap to intake manifold, with a PCV valve in-line just above the oil trap; and the other, valvecover/oil filler to forward air cleaner. I recall that I did it that way because I used the B18, alloy intake manifold. The other way around is standard for the B20 and doesn't take a PCV valve.
Bob S.