I wouldn't trust a box that was mass manufactured without thouroughly inspecting it. Even then, your better off designing and building something yourself, especially if you go ported because the store bought ones are ussually tuned ridiculously high. Also you will save yourself some decent cash. If you want sound quality I would stay away from kicker. Also those alpine type X's would probably like a bit more power, plus i think they only come in dual 4ohm so unless your amp is 1ohm stable you might be screwed. The 12" type r's could probably handle 650 each, and if you decided to go to the 15" they would easily take it (and get lower!), and both are offered in dual 2ohm and 4ohm.

For $1500 you should be able to get some pretty amazing subs. I love the Diamond Audio D6's that I have which can handle 700Wrms each, but they were bought of E-Bay with zero warranty, as there are no Canadian dealer that I know of. Check with Mr2NR or SmartAss they can probably hook you up and give you some better advice than me. Or check out the for sale section, there are usually some ok deals.