i have a 1999 dodge dakota extended cab and recently acquired 4 12" jl audio w3v2's. any suggestions as to how to approach installing my new subs,i.e. sealed vs. ported, downfiring,etc? i have no problem sacrificing my back seat and am looking to push about 250-300w rms to each sub via two kicker kx600.1 amplifiers.  

Well, first of all, what kind of music do you listen to the most.  If it's country, rock, metal, etc. then you'll be better off with a sealed for the tight bass response.  However if you're normally listening to hip hop and rap then you'd like the ported better because of the ability to get lower louder than a sealed enclosure.  If SPL is your main goal then a ported enclosure with all 4 subs sharing the same air space will be loudest.  If you want loud but with decent SQ then you'll want to build the enclosure with seperate ported spaces for each subwoofer.  I can recommend and even draw up all kinds of enclosure idea's, however it comes down to what your listening preferences and goals of the system are to decide what you end up with.  

Haveing worked on those trucks , I would say stick with sealed with the air space you will have to work with . That way you can make a cool lookin box and have room to mount all your amps and power distributiuon stuff. Jeff Meece California Soundworks Car Audio And Electronics Top 100 Installer .