ported or sealed sub enclosure?

So i'm building a Sub-woofer enclosure for a friend, and wanted some opinions on whether to go with a sealed or ported design. Vehicle- 2009 Hyundai 4dr sedan, Sub- (1) 12w3v2d4, Amp- TMA T2 250.1 monoblock.

It's obviously going in the trunk, so......  Pro's and Com's of Vented vs. Sealed? I just want it to sound as good as it can. Thanks for any and all input!

http://mobile.jlaudio.com/pdfs/12W3v2_MAN.pdf

I would find out several more criteria about this customer before undertaking the build.  While either sealed or vented suits this subwoofer just fine (Qes .443, Fs 24 Hz, EBP 54), the actual size and weight of the vented box will be nearly twice that of the sealed.  So, how else is this trunk to be used?  Will it need to accomodate a baby stroller or luggage for vacations, maybe a golf bag?  Find out all these things and map out the box's footprint with your friend.

Pros / cons are minimal with this sub.  Look to his front soundstage for a clue on how to approach the sub build:  high quality components with amplified, detailed sound?  No amplified front soundstage at all, or minimal attention to front sound?  If high quality fronts are the focus here, I'd tend to sealed for truest SQ with this JL sub...obviously rocking the street with the beat isn't the primary appeal.  On the other hand, if this sub is the focus of the "system", I'd tend to maximize it with the larger ported box to eek out the greater db level.

Thanks for the input! Front soundstage is amplified and quality components are being used, so I will go with the sealed. Plus it gives easier access to the spare tire.... Oh, better SQ too.