Box design

Looking for the best possible box designed for 4 8 in sound cubed SD 2 8-in dual 2-ohm coil in a 2006 Silverado extended cab four door preferably a vented enclosure and one that contours to the rear of the cab and the floor I would like to box to be dual purpose meaning it would be the seat that you set on for the rear seat and obviously the speaker box itself I have four 12s in there now of all random different kinds in a pretty basic just big ass square sealed box hoping these will be louder but a little up in the air about it not sure if they will be able to compete with the 412 even though these are better quality what are y'all what are your all of your thoughts and opinions Collins concerns anybody got to design up there for me I could build something with that is to spec for these woofers..??   Thank you all sorry about the long winded novel here...

https://www.facebook.com/groups/405747358529837/   hit me up at Ugly Box Enclosures on FB i can take care of you and build it . or make the plans. your gonna want a solid made box for all that air them thangs move