There appears to be some confusion over "BFA style" plugs. The AQ BFA plug looks surprisingly like a Nordost Z-Plug. I have used the Z-plug often for terminating speaker cable and it works very well, possibly providing the tightest connection I've encountered. The beauty of this fit is that, unlike spades, you don't have to keep checking the screws for tightness. The Z-plug, by nature is "sprung" and puts constant tension on the inside of the terminal.
The BFA plugs sold by AQ and others appear to be the same concept as the Z-plug.
When I go to the BFA (the federation), the plug they show is not the same as the Nordost or AQ. The Nordost Z-plug will work in a BFA terminal (I previously used Z-plugs in an Arcam Alpha 10), however, they seem to defeat the purpose of the BFA, which was to insulate the outside of the plug to prevent electrocution.
Interesting stuff! It appears that Nordost (and others) have created a plug that works (extremely well) as a banana plug in a standard terminal, but also works in a BFA certified terminal.
Oh, sorry, I don't know anything about Vandersteens......
Enjoy,
TIC