Enclosure recomendations for 2 sundown zv6 18"

[BrandonScott]

 I have a question for anyome who can help. I just ordered 2 sundown zv6 18" subs. My first big boy subs. I know they each call for 7 cubic ft, with 112 cubic inches of port area @ 32 hertz. So if im making a dual 18 box, instead of single boxes, do I need 14 cubes, 224 cubic inches of port? Or would it be better to go like 12-13 cubic ft and a little less port area since they are in the same box? Also, would it be better to run single boxes? Or a dual? I have an suv so space isn't an issue, and I am going for spl/DB scores. Anyone have any opinions feel free to chime in please. Thanks for any input.

Also, I have been looking at a box design by intune designs, anyone ever used it or seen the design they have? Thanks guys. I added a photo of the design im looking at. 

[Joe X]

Cut port area when you are looking for plain SPL does not sound right, do software modeling on the power you intend to run maximizing volume and port area as possible within the space you have to work with and very important keeping proper port clearance, single box not dual boxes, the type of box you show is right for SUVs. Just bear in mind that plain SPL boxes don't sound that nice, if you want to to sound nice, you can't go far above sundown specs. 

[BrandonScott]

Ok, thank you for explaining that more in depth.  So, im running a 64ah lithium headway bank right now, yellow top under the hood, and an xs power super capacitor from the headway to my amp. Im currently running a marts digital 8k. I know that's not ideal for subs this nice, but it's what I have for the moment until I can get my new alternator in and more lithium.  So I'm thinking I will go woth the intune box design that I posted for now and see how it holds up. When I get more power I may switch them to single boxes. 

[Joe X]

Ok just make sure that with the external dimensions of that box you still have 5 inches of clearance to the rear gate in your SUV so that the port operates properly.

[BrandonScott]

Would it be a bad idea to do the subs up, port up? Or is it better firing to the rear in this case?

Also,  I've been fooling around with sub box pro, and I came up with this box design. Except the subs would be up top firing towards the roof, and they would be mounted diagonally. See what you think. I just put the subs in the calculation so it would counter in the space they will take up. And this program doesnt give the option to mount the subs up or change the location of the port. Also, id be doing triple or 4 baffles. 

[Joe X]

In my opinion the first design is far better as it doesn't have potential loading issues and also with the second design you need 10" of port clearance instead of 5" like with the first design.