I may very well be wrong...ahh, hell, no I'm not!
lolz. what makes me laugh is people who make claims like "that's not internal" but can't themselves definitively define what "internal" is, mostly because they themselves don't understand in the least, but also because this type of power and skill is not just he result of one thing (i.e. dan tien), but the culmination / relationship between all the parts, like dan tien, ming men, huan yuan "energy", peng "energy", spiral force and tai chi and so on.
i thought Lorel said it quite well -
I am just suggesting that if their methods produce relaxed bodies that create kuzushi on contact, non-telegraphed strikes etc., then I will study their methods even if their systems are not classified as "internal" by some people
if somebody comes to see me and i can take their center from first contact (and i generally can), then we have nothing else to talk about. if they really understand what "using the dan tien" means, then i wouldn't be able to capture them so easily.