http://www.parts-express.com/pe/showdetl.cfm?Partnumber=295-468

I know a little about all the "T/S parameters", but I'm still very much an amateur at home/car audio. Do you think I should get a premade box like this http://www.parts-express.com/pe/showdetl.cfm?Partnumber=302-830 ? Or if I should build my own, what type, dimensions, etc should it be? Thanks in advance for the help!
BTW it's for a 26x18x7 room not, but you guys know more about this than Home Audio people

^not a car^