Straight swap more or less, but yeah it's a crap motor.

The only reason people use them is to put a VTEC head on it, so if you're against VTEC then I don't see why you're bothering.

Grab another B18B2, rebuild it, then swap later.

You'll be wasting hundreds of $$$ or more to go porting a B20 head for essentially nothing. It's not just the ports that suck, it's the combustion chambers, camshaft profiles, lack of VTEC, valvetrain isn't sporty either. It's a dud engine pretty much. Only the block is worth keeping for a frank-build. WOTAM otherwise.