I'm not sure if you misunderstood me or vice versa.
When I modified rojo's design, I changed both the cabinet size and the tuning frequency of the port. The cabinet volume and port match each other, but they're not ideal for the driver because I wanted a lower -3db point.
It's also practically impossible to modify the port size once it's cabinet is built because the MFD panels are glued.
As for "felt rather than heard", I was looking for bass that can be felt, not just heard.