Consider xtz Cinema sub 1.
Similar price. And it can be used as both sealed and ported.
Closing the port on the ported subwoofer won't really make it as a sealed subwoofer.
The enclosure design/size for ported and sealed are different.
If the requirement is a sealed sub, go for one (do not buy ported/slotted and close the port/slot)
Closing the port/slot on ported/slotted sub mainly changes the roll off at the lower frequencies which may help to adjust with room gain.
Closing port won't give the punch of a sealed subwoofer at lower mid frequencies.