help need with ported sub box design

[oscarjw]

okay, well hears the problem
i really like the focal access 25a1 sub woofer as it fits my specification pretty much perfectly and matches my focal door speakers, its also 200w rms at 4 ohms and my amp is 150w rms at 4 ohms so a pretty good match there too
focal are also a good brand and i like them so though i would give there sub a try
but focal recommend a ported inclosure, and so i am of course probably going to listen to that when constructing the box for this sub
my problem is the fact that this sub is going to be used in a false floor concept in which you just see the sub flat of the floor of the boot i was going to construct a sub box that sits of the floor of the boot with the amp to the right and cover it with another sheet of mdf with a cut out for the sub only and carpeted
but i can't find a pre made port that matches any of the require port sizes that focal recommend and really don't know which dimensions to go about choosing for this sub its quite shallow at 4.5" so a box of a maxium of about 7" deep with 3/4" mdf would be perfect, i just have no idea how to go about this port ? any help i will like the box recommendations thanks

 

[oscarjw]

http://www.crutchfield.com/S-sJ7VH7...Details/HandsOnResearchWrapper.aspx?i=09125A1 heres the link to the recommended enclsure sizes how closely do i need to stick to these, a little confused if some wiz could clear this up for me that would be great, fyi they don't recomend sealed enclsure and people say these subs sq are amazing ported so though i would give it a go.

 

[oscarjw]

anyone?