Hi Hi Ho (why do the Seven Dwarfs come to mind there
),
That looks like a perfectly acceptable kit. Note that in buying the enclosures you're basically doubling the cost. This is an important point for anyone thinking of building DIY speakers - the cost of making and transporting good cabinets is very expensive (for manufacturers).
Many cheap loudspeakers use boxes made of chipboard (or worse) in an attempt to lower shipping weight. If a manufacturer uses MDF (which, I believe, most of the good ones do) then they're handling and shipping a cumbersome, heavy product, which also chucks out loads of dangerous dust when machined. Obviously, this all adds to the cost you pay.
The point here is that you make your major cost saving by making the boxes yourself. I'd expect the MDF for a pair of those units would cost well under 20USD.
The pdf drawing on the site isn't great, but you basically need to make a box out of straight sided panels. You can ignore the rounded over edges - make a solid, sealed box, and round the edges over on a router table if you've got/can get access to one. Make sure you wear a good dust mask at all times.
You don't have to veneer the boxes (it can be tricky). A light wash of Zinsser B-I-N (a 1pt tin will easily do it), followed by a quick sand with wet-and-dry paper (with some water) will yield a surface that you can easily spray - even with cans.
I'm now using a HVLP system for spraying, but my first speaker projects were all done with tins (and a vastly inferior primer to B-I-N). You can even get automotive places to mix up special 'blends' in cans - I did a few speakers white, with a metallic blue sheen (not as tacky as it sounds).
It's totally up to you, that's the beauty of D-I-Y!
