Its an infinite baffle speaker designed for the large volume of a car door for example. While a small sealed enclosure will seriously limit the lower bandwidth of this speaker its still preferred over an open enclosure so you have front to rear acoustic isolation.
You can port anything with a small PVC tube. But with this speaker in the size of enclosure I'm envisioning, you're probably going to get a pronounced single note effect. It wouldn't be too hard to trial and error with a couple of different tube lengths. There's just no way to model this in advance.
Go with sealed. Its predictable in this application, both sonically and in power handling. And just like Mike said, it doesn't have to be a complete enclosure as long as you have good isolation front to rear.