I think it's pretty much common knowledge. I remember being amazed when it first came out, I might be fantasising here but wasn't there an ad with a Japanese guy saying something like "Very clever, these Germans"?On a side note, i wonder how many people know this engine is not really a v6 at all and actually a staggered 6, or Vee Reihenmotor ( inline vee) in German. They wanted a 6 cyl motor for more power but an inline 6 was too long to be mounted transversely in the Mk3/corrado and a v6 with 60 or 90 degree banks would eat into crumple zone space and require vehicle lenthening.
The v6 uses today are still actually VR6s, but have even narrower 10.5 degree angles between the staggered 'banks'. The cylinders altnerate left -right either side of the crankshaft with no cylinders being opposite to another like in a normal Vee. This design allows much more compatness, and also means less moving parts and increases simplicity- this halves the number of camshafts required for example. It also means the engine is almost as smooth as an inherently better design for smoothness then a 60 degree v6.
By sticking two VR4s two, VR6s or VR8s together you get the W8, W12 and W16 engines, all very compact for their size. Very Clever from VW that.