I haven't heard the FE126NV2. The "NV2" is the successor of the NV. The NV2 uses more
environmentally friendly adhesives and the spec sheet is now a download to save paper.
Personally, I like good glue (the kind that deforms babies, causes cancer in mice, and makes you light-headed) and by god if I'm paying $73 for a driver, I want some paper literature.
But really, I've read that the new model offers less upper-mid distortion. Whether that is audible is another consideration. If it is audible, does it matter if you cross-over to a tweeter or Heil? I guess the transition frequency matters here.
Just my 2 pesos...