Lucky 8 is a retailer, not a fab shop per say. No idea on the other company being American or not, never heard of them.
They are also listed as bump stop extensions, NOT strut/shock extensions. They achieve the lift, best I can tell, by extending the arms for the height sensors.
So again, they are not spacers for the struts, but for the bump stops. And also again, screwing with the mounts for the air strut is stupid in my experience and opinion.
If you want to mess with the MkIII suspension, either do it right or leave it be. People a lot smarter than yourself designed it to work the best, under as many conditions possible.