personally, i would want the b18c1 over the b16 mainly just being it has some extra torque. A b16 has hardly any more torque than my little d16 does.
Altho, it does cost more for the swap. I think it depends what you are wanting to do w/ this, just swap it and be done w/ it or boost it later or what? If you are planning on boosting, i think i would just get the b16 cuz its cheaper and will still be extremely fun. If your wanting to just swap it in and be done or build it up for all motor, id say go w/ the b18c1