i manufacture spark plugs.
most of what you think you know about spark plugs is propaganda[i.e., not to be believed].
i care to report for you what ac and autolite reported to me about their platinum-attached spark plugs...none ever made the 100,000 mile mark...but the secret warranty program persuaded you and the dot, doe that those ignition components really lasted for 100k miles.
that cannot happen.
platinum electrodes are a buzz. sounds good. makes you feel fuzzy. but they are a joke. and the four ground electrode boschies are the biggest joke of all.
if you really want to discuss ignition components, the important one is the coil. much more important than the spark plug. how many of you out there are having problems with them?
my info is that coils are a major problem. and just not on vw's.