Everybody knows VWs are junk anyways Arco...
I hear people say this about VW's but in my family we have a 1960 bug convertible that has been in the family since new. It's on its original engine and trans is 62 yrs old still driven several times a week and still sounds like a singer sewing machine. In comparison show me a 62 yr old Honda still running? A 62 yr old Toyota? Mmmm wait you won't find one haha.
I'm just poking fun here. All brands have issues of some sort. The only car that has left my Dad stranded on the side of the road? Was a Toyota (1986 Celica he bought new) and the only car that has left me stranded on the side of the road was a Toyota (1984 Corolla) haha.
Now back to the 508 oil. Huge debate over this on the VW Forums. Some people still run 502 oil in their 508 spec'd cars. The problem i have with 502 in this application is the emissions issues with it's use over time possibly? 502 could and i say could also contribute to more carbon on the valves as well. I believe the 508 is there 1. Fuel economy 2. Emissions 3. For the start/stop system. All 3 of these reasons a 20w just makes more sense.
Now if your building yourself a 600whp GLI or GTI then go by what the engine builder says to use.
I have found when I had a mk6 GTI i never had to add oil to the car on 5 yrs of owning it. My new mk7.5 (purchased new in October 2020) I've had to add oil several times. About 4-6 oz ever 4k miles or so. I have considered switching to a 0-30 504 (M1 ESP 0w30) being that it too is low to mid saps like the 508 but just a weight higher. I realize this will not be approved by VW but might help with the oil consumption.
Additionally, i have never owned a car where the manual states to not use more than a half a qt of a non approved oil or engine damage may occur? So what would happen? It will damage the emissions system causing a complete failure?? Makes no sense to me🤔