Talking of Spark Plug I was told by a VW Dealer the recommended interval is now 60K for the BYD engine in the ED30 when I asked for the cost for the 40K service while getting Mrs PG car done today.
I won't be waiting that long, it really does seam VW are pushing the limits of the parts these days and I wonder if this is to help things like the cost of ownership comparisons ???
60k miles has always been the replacement timescale for all the 2.0 TFSI engines. And that is because just like most 'modern' engineered automotive things, they are specifically designed to last much longer than 'old skool' stuff. Same with longlife engine oils, H7 halogen bulbs, etc.
And yes, longer intervals do help with cost of ownership, but then VAG are no different to say Ford, Vauxhall, BMW, Toyota, Honda or whoever. Modern spark plugs really are vastly better than the Champion 7YC which you have to replace in your Suffolk Colt lawnmower every spring because the ba$tard wont start, and you end up snapping the starting pull cord in frustration!!!
However, all that said above, TTs learned advice, particularly on a modified car which is driven hard - is to basically reduce the intervals of routine consumables by either a third or a half - so plugs & air filter every 30k, oil & filter every 5k, BFC every year. Obviously, if you can do those jobs yourself, if wont cost as much as if the garage has to do them.