There are a few Sub Design sites online that can help with the box design and explain the various pros and cons on the options, i.e sealed, ported, passive radiator, etc. You will need to get the driver characteristics off the manufacturers website.
Also a few good DIY forums, google these and you might find a similar project.
I am looking at replacing my 15" sealed Rythmik sub with 2x CSS SDX12 or 2x 15" that fit in a smaller enclosure with a similar pro amp to you. I don't think there is anything special in the amp connection there are a few ways I know of, if it i