not enough bass into cabin

I don't think my system sounds loud enough inside the cabin because it is closed off within the trunk.  My rear seats fold down, and I know 2 12w3's can do better than what I'm hearing.  I want it to look clean and was thinking that port tubes are the answer rather than cutting a hole in the top part of the trim panel above the box.  Question is, how many do you think I need based on the pic and what diameter?  I probably can only do 3" at the most because thats how much room there is in the trim panel and top of the trunk.  Would three 3" diameter port tubes be enough to get more bass into the rear of the trunk and into the cabin?

JL AUDIO 12W3V2 D2's powered by an Alpine MRD-M1005

[url]http://www.crutchfield.com/S-V5zGh3RCmlK/cgi-bin/ProdGroup.asp?g=745[/url]

[img]http://dodgeintrepid.net/photopost/data/510/5861box8-med.jpg[/img]

Um.  Okay looking at your install your woofers look like they're fighting each other.  Don't point them at each other like that.

I've seen very similar installs with *very* poor results.  Have you noticed the boxes on the market have the subs on the same plane? 

Reverse the polarity on one of the subs and see if it doesn't improve a bit.  If it does, you need to redo your entire install.