DIY subwoofer in Canada

Hello,

I have a Paradigm PS-1000 v4 subwoofer and have no complaints at all with it, but lately I have been thinking about whether I could sell it for say $450 CDN and try to build a better sub for around the same money. I have zero woodworking skills, but my friend is a whiz at it. He builds his own bass guitars with fabulous wood inlays. Not wanting to pay duty and heavy-duty shipping costs to order a woofer and plate amp from Parts Express, are there any Canadian sources for an excellent quality driver and plate amp at a reasonable price? Any recommendations on a 12-inch driver and 200 watt plate amp that would give me response to 20 hertz and good output and musicality in a large listening room (14 by 24 feet)? I assume a sealed sub would be easier to get right than a ported one. I would need to get plans for that. Thanks in advance.
Dave