Cams of any B series are interchangable.
b16 headers will not fit b16b/b18a,b,cX unless specified because of the deck height differences, but b18 headers will fit b16's, just hang down a bit.
ITR intake manifolds fit B16a heads.
Skunk2 and AEBS make intake manifolds for all B series motors.
There's lots more, gotta be a bit more specific.