Truth be told, I don't know that much about the project. I just know that I love the sound of the SID chip and that I've been wanting get into this DIY electronics/MIDI/synth business for a while. I've been reading up on the project, and it seems like it'll be doable, albeit with a bit of a learning curve.
Anyway, I figured from the "partial" in the description, that it wasn't going to be everything... but just from looking around, 8x 6582s seem like they're going to be hard-ish to come by. That, and the fact that it comes bundled with a bunch of other necessary stuff saves me the trouble of hunting it all down separately.