Use WinISD Pro Alpha. Anyway, i'll do the numbers for you now. As it is, your box is tuned to 29Hz, which is great for music but may be a bit high for home theater. If you don't have a high pass filter you risk bottoming out the sub, but not with that amp.
Is it worth redesigning the box a bit? I'd say yes. But only if you also get a bigger amp to go with it.
Is it worth redesigning the box a bit? I'd say yes. But only if you also get a bigger amp to go with it.