The only Mazda option is the Pro Kit (black springs). Doesn't look like much difference between the two kits.
As for "not assembled", I was told by the fitters that the springs and the shocks weren't braced together (I gave them a sealed box direct from postage) so had to be put together, not a straight bolt-on.
As for the combination of them, it looks very much like a B8 shock with Eibach spring. I doubt there's much difference in shock (if at all) since when you go above the B12 in number, you're in serious motorsport areas (from what I've read).
Tempting yes, but with a backlog in postage, expect to wait a bit. I got mine in around 4 weeks from order.