VW is not very popular in terms of market share. It is more of a niche' player, offering several models with diesel drivetrains, which are a small minority of US passenger vehicle sales.
There is a good subculture of VW stuff, but the aftermarket and tuning popularity is dwarfed by GM products, Ford, and Chrysler.
The big benefit for me is that back in the late 70's and early 80's, Chrysler partnered with VW to supply drivetrains for many of the small front wheel drive offerings of the time. That was before Chrysler debuted their own 2.2L 4-banger and associated drivetrain components.
The Chrysler stuff is similar to the VW designs in many ways, but generally won't bolt together with the VW goodies. The key is knowing which models and years used VW components, and when the switch to Chrysler drivetrains took place.
I'm able to use "mostly" bolt-in components from the correct selection of vehicles to put this VW diesel drivetrain into my Rampage. The front motor mount will have to be cut apart and modified for clearance around the injection pump, but the rest of the bracketry has been pulled from a variety of junkyard cars and trucks.
Steve