hey buddy,
i have the same delima as yourself...i got a 97 silverado ext cab, and need to keep the rear seat due to kids...
my friend built me a box, downward firing sealed enclosure for two Sundown E8's, they are getting about 250-300 watts rms, and they bang...they get low as well.
with that being said, after a year of having this, i'm wanting MORE power...
I'm trying to get a box, same design, but fit the new Sundown SA8's...the woofer depth is the problem i'm running into...if i can get that figured out, i got a Kicker ZX1500 that will feed these subs all the power i'll need!!!
so, if you can get this box figured out, let me know!