I want to use the HiVi L6-4R woofers, mainly because no one's used them that I know of yet, and the things are just so darn sexy

My first question is, how do you know what size cabinet these drivers will play well in? My background comes from car audio, but figuring that out was easy because the ported or sealed air space was spelled out in the sub's spec sheet.
This is what I've found as far as the cabinet requirements •F3 of 55Hz in 12 liters (0.42cf) enclosure with 1.5" port by 4" long. But I read on PETT that this isn't correct, and I need to add about 3 liters which would bump the ported cabinet up to about 0.5cf enclosure, correct? How did they arrive at those #s??
My second question is, how do you go about picking a tweeter that will work w/ these woofers?
This probably isn't protocal for picking drivers to use in a design (just because they look sexy), but I have to start somewhere! Any suggestions from anyone or direction?