Which SD2s to put in a crew cab chevy

[peont]

I was wondering if it would be better to put behind the back seat of my 06 chvey crew cab 2500hd 2 SD2 8s ported or 2 SD2 10s sealed? The measurements behind the seat are of the enclosure I have now is sealed with the length 47 3/4", height 14", top depth 5", and bottom depth of 7 3/4". I could take out the vents behind my seat and get my box length to around 56" if I get a custom box made. This is my box I have behind the seat now http://www.ebay.com/itm/CHEVY-SILVERADO-CREWCAB-HD-2001-07-10-GREY-SUBWOOFER-SUB-ENCLOSURE-BOX-/281068185596?pt=US_Speaker_Sub_Enclosures&hash=item4170f827fc&vxp=mtr Or would it be better to put them downfire in an enclosure like this sealed or ported? http://subthump.com/product_info.php?cPath=1_72&products_id=57

[ghettobasshead]

Ported with 2 sundown e8s the sd2 8's should not be ported and I think you will like ported better than sealed, depending what music you listen to but since you on the forum then you must listen to decaf lol

[peont]

What about the sd2 10 do they sound good ported?