Custom box help....(sketchup of box)

[Hovx]

Hello Everyone!

I am planning on building my own custom box for dual 12" subwoofers. I drew up two boxes in google sketch up. I put a link to a picture of them below. The further back box that is more to the left is a factory box I have right now. Its dimensions are 34.5" width. 15" height. 9 " top depth. 12.5" Bottom depth. 3/4" wood thickness. According to the RE Box Calculator is has about 2.14ft^3 as is tuned to approx 33 hz.

The closer box is the one I would like to build. The reason for uploading this picture was to see if such a box would be a good idea, So the exact math hasn't been worked out to make her perfect. But I want to know if it I should continue to figure out the best way to build box or not before I get into it and have it turn out to not work and waste my time. I did find the dimensions of the box to get a rough idea.

34.5" Width. 15" Height. 0'' top depth (1.5" if you count the top of back board, but it doesn't affect the space inside the box) 13.5 bottom depth. Front vertical face 6.94. angled front face where the subs are 14".

The wood thickness is 1.5". I have no idea the ;tuning since I didn't create a port. If anyone could point me to a good place to figure out proper porting size It would really be appreciated! I do want to make a square port. The cubic feet is strangely the same as the other box. 2.14ft^3.

I used similar measurements because the box I have now fits perfectly between my rear wheel wells give or take an inch or so and leaves me plenty of trunk space (the factory box hits pretty hard. Hopefully I can get this one to hit harder!). I can make it bigger if need be. Also, I drive a Hyundai Tiburon which is a coupe hatch back. I want to use this design to use the natural curve of the hatch to channel the sound better.

Let me know what you think!

My boxes: http://www.flickr.com/photos/100066360@N06/9471697948/

PS: My father frames houses as his occupation. I have access to all the tools necessary to make this box. I also have helped him a lot during my life so I feel confident in making the cuts. If not then he certainly will be able to. Also if you don't like the box point out what you don't like or what flaws you see. Calling it a dumb or stupid idea isn't going to help anyone. Again Thanks!