You're both right guys,
so far, we haven't heard anybody complaining about'em being a hard-to-drive speakers set, right? From this point of view, we can say for sure they're all 8 Ohms rated. In other hand, the S&V guys have been very specifics in regard to the low impedance found on bench tests, though ( 2.5 - 4 Ohms, being 4 Ohms the nominal impedance... really weird, isn't it?).
Let's wait for some more opinions though.
Cheers.