Sorry I missed this earlier.

It really depends on your goals. If you want the most SPL out of the sub, a larger ported box will give you more. I have designed a box for 10" subs which gives pretty good SQ along with a lot of SPL that is about the same size as the typical vented enclosure, but with a tapered port that gives it just a little more pass band and a bit less of the "one note' effect that most ported boxes tend to exhibit.

It is nowhere close to the DB in SQ and the speaker sounds excellent in a sealed box as well, but you lose a touch of SPL going that route.

Just depends on how important the SQ factor is. You may find the car isn't friendly to the larger enclosure and tends to be very one notish, or you may find it totally agrees with it.

What kind of car is it? How much power are you putting on it?

Those questions along with a detailed explanation of the goal will help tell you what will work best.

From my own experience, the DB is awesome for it's size. You can also do a regular 4th order BP with this sub and get good results in a slightly smaller or larger enclosure. (mine is smaller). The DB gives you more flexibility which is why my friends car has the tapered port design. It is still very loud and very efficient. Give us some more details and lets see what we can come up with,

Take care,
Robert

If you have the patience to baffle the sub and seal the trunk, it sounds awesome.

Two of the best SQ cars I ever did or even heard were IB trunks. One was the Blues audio thunderchicken and the other was an 85 Monte Carlo we did. Lots of work, but well worth the effort. SPL was high enough for most even with an IB set up. Of course, you have lots of options.

Let us know what you end up doing and how it turns out.

Robert