Bob,
<<<... Other options to make an engine breath better would be to add a cam
with bigger lobes. But I have gotten more than one call from sad lads that
put a non stock cam with more than stock lift and duration in there vans they
said had to down shift at the smallest hill even when they had a tail wind>>>

The 1.3 ratio rockers combined with the increased lift AND duration from the
stock cam AND the other changes have allowed me to cruise through town in
fifth with the engine turning @2100~2200 rpm and go up and down the hills  at
45 mph with easily.  On all but the steepest hills, I can maintain 55 mph in
fifth gear, engine is turning @2800~2900 RPMs, going with traffic.  I can
take the engine down to 1500 rpm in fifth gear and back up smoothly, going
with the flow of traffic.

AND I have not only increased the power, But the economy as well.

Does your Big Valve get better mileage?

I think that going to bigger valves would be needed if the stroke or bore is
much increased beyond a small increase.

I have also changed the exhaust and match ported the intake system.

VW should have done what I did ... and many would not be complaining...

Robert