You can use either of those heads, but the b16a head has a slightly larger combustion chamber which makes detonation a little less of a problem, which would an even more serious issue when some form of FI is used. It's just easier to deal with because there is slightly less risk of detonation which means less headache and worry in the long run. I've also seen that the b16a heads are easier to get and slightly cheaper as well...but I guess that depends on how much supply is available and the demand in your area for them.