2: yes

No software can put in displacement adjustments without specific info on the items involved (and most don't include any adjustments at all). You also need to adjust the internal displacement for any bracing and any other speakers, horns etc. A popular rule of thumb is to build in at least a 15% fudge factor and add bracing until the box tuning is correct (involves measuring the system impedance curve to calculate the system H and Alpha values).

Jeff Robinson