Chris, as you know, speaker impedance commonly varies significantly with frequency, and usually the manufacturer rates it at an average figure(the M80 is an exception, since its 8 ohm nature over the majority of the frequency range would justify a 6 ohm average rating). This may simply be a determination that the average for the VP150 is more realistically 8 rather than 6 ohms and that the 6 ohm rating may be confusing to some users who think in terms of 8 and 4 ohms. It seems unlikely that there was actually a change in the drivers so that their impedance was increased. In any case, the difference is nothing to be concerned about.
Yeah, I'm not worried, just curious (good thing I'm not a cat; I would have long since used up all my lives). I don't think there was a change in the drivers either, but was wondering if the crossover design was tweaked at all--which could also change the impedance. Just wanted to know if it was a design, or a labeling change.
Probably just a sticker/label error. My VP150v2 says 6ohms and it has always been stated as such under the manufacturers specifications. What does it say on the stickers on the box?