I have over 200,000 miles on my 1.9L and usually rev it up
 > near 5,000 RPM before each shift - and the previous owner did same and
 > cruised the highways of Kansas for hours at 4,500 RPM.

Mmmmmmm.... this engine simply doesn't like to run over 4000rpm.
Over that, the power curve is gone.
Running an engine that way for that long is simple luck.

I have own 17 motorcycles (mostly air cooled), 1 years of racing in formula
ford 1600 and I have 978 hours log as a private pilot, mostly on Cessna
172, Arrows and twin cougar. I have learned with time to feel and
understand an engine. Our airplane engine are air-cooled opposed flat 4
very similar to the VW (I know some guys who fly kit plane with VW beetle
engine!!!!) and for those who don't know we have to adjust mixture (rich /
poor) on all plane depending of altitude, pressure and other stuff. Also on
some other plane the pitch of the blade and other more complicated stuff
most constantly be monitor or adjusted. We have learned to manage engine
for optimum performance, reliability and endurance. (My life depend on
those old Continental / Lyncoming engine)

All that stuff to tell you that I don't like the noise of this engine (2.1)
over 4000 RPM, I would never cruise over 60mph or 3400rpm (consumption wise
also). The vibration and roar it does at 4000+ rpm doesn't sound right. The
VW engine is a "Driver wanted" engine for real, or should they say; "Pilot
wanted". With good care & maintenance (put some good oil and change it
often) and some wise gear change (Trany), there is no reason that the flat
4 would not last for well over 250k mile.

Sadly many VW Vanagon drivers don't know shit about running an underpowered
vehicle. They just press the gas pedal and put some gas.
Underpowered vehicle need careful & understanding drivers.

Lol, Ben
http://www3.sympatico.ca/huotx/engine1.htm