Dj_efk posted this excellent oil spec comparison tool from Lubrizol, who incidentally supply the oil additive packages to many of the major manufacturers -
https://online.lubrizol.com/relperftool/pc.html
I use that too. It's nice. I use it mostly to find minimum HTHS of various oils.
But they note that you can't compare across various industry specs (e.g. PSA to VW), although I do do it sometimes, like ACEA to API.
The Castrol SLX LL2 in that post you linked to, was a 506.01? (505.01 for 15k km/1yr fixed , or 506.01 for 30k km/2yr variable I think it was originally)
I, as part of the public, definitely would not accept 150,000 miles (or km!).
And I think later on (the post is from 2003), especially BMW folks, kept complaning about how these long intervals were ruining engines. But who knows. Simiar mentality with Peugeot, people here opting for 5W-40 in the Prince BMW/Peugeot engines, chalking up the 5W-30 and long life claims to eco-marketing. There definitely was an eco push back then, hybrids, 0W-20 HTHS 2.6 that wasn't specced by VW until only a few years ago. Who knows. *shrug*
The post says the Castrol test was just that, so probably done in controlled conditions, but what about applicability to real life driving and wear and tear? But hey, Castrol/VW, brothers in arms (at least back then), big marketing for Castrol probably too, and with a 150,000 mi claim! wow! I take it with a big grain of salt. Was the long life really quoted for up to 30,000 MILES in the UK? I think it was up to 30,000 km in Europe?
Does anyone know if Audi/VAG allows any of the very new specs to be used in the PD TDI engines? 508.88/509.99, 511.00, just noticed them on the Lubrizol page. All have a min. HTHS of 3.5.
Maybe the 511.00 is for cars with particulate filters in ultra low sulphur fuel areas, 508.88/509.99 for same in areas with higher sulphur content fuel? (noticed low and high TBN minimums, respectively). Just guessing. Maybe I'll give the Audi dealer a call again, though I'll probably stick with old-school 5W-40 505.01 anyway.