Firstly, I wouldn't get a VW dealer to service my car. They charge £150 just for an oil and filter change which is ridiculous. This is not representative of the cost of the oil they use. They charge a fortune, but provide you with a lovely receptionist at the front desk, a nice place to sit whilst you wait for your repairs, maybe a courtesy car, and tasty coffee from a bean-to-cup machine. These things are not free.

This oil is of the highest grade as set by the American Petroleum Institute and it's European counterpart, ACEA. For petrol and turbo petrol cars for everyday driving this will be good. Do you think there is something special or magical about VAG engines? Nope. Very few car manufacturers set their own standards, and when they do it's to ensure they pass the ever stringent European emissions standards, which get tougher every year. If their cars fail, they can not sell their cars on the European market. Many cars/engines have been pulled out of sale because of failing to meet these standards. My beloved Mazda RX8 is one example. That crazy rotary engine just could not be made any cleaner. All the Japanese car manufacturers require oils that perform to the highest API/ACEA standards including high performance engines from Honda and Mitsubishi. The oils with VW group specs don't have anything else special in them. All modern fully synthetic oils that meet the highest API/ACEA grades have similar additives.

I remember when I had a Volvo with the lovely (but thirsty) 5 cylinder turbocharged 2.3 engine, the oil spec changed one year. I asked why, and this was because it offered better economy and emissions, but actually offered less protection to the engine. The engine itself was exactly the same.

With regards to track days; when making engines, car manufacturers balance performance with emissions, economy and reliability. As customers or users of these cars we sometimes want a different balance. When I take my car on a track day, I change my oil to a race spec Motul or Fuchs brand with a very high viscosity. This is what my engine builder recommends. This offers my engine the best protection when I'm revving the s**t out of it, at the expense of emissions.

Now modern diesel engines are fussier. However, a lot of the oil spec. recommendations are to reduce emissions. It doesn't necessarily mean the engine is better protected.

By the way, I'm not talking garbage, I'm a chemist and have chemical engineering friends who work in the oil industry. I often annoy them with questions or this nature. I'm also a car nut and have experience of engine building. You are right though, you won't go wrong if you stick to the manufacturers recommendations, but don't always think they are prescribed to maximise longevity of your beloved car. If you are in the know, it's okay to venture outside of their direction to achieve other goals.

Think of this: there are many car servicing franchises out there (HiQ, Kwik Fit, Chemix etc.) who will offer you servicing at far lower prices than the dealership. Do you think they have 10+ different oil types with different viscosities and specifications in their garage? No, they usually have large barrels of 4 or 5 or so. Most decent garages will fill your car with the highest grade from an okay brand. They will do this without invalidating your warranty. These companies are not stupid (for the most part) and would not risk the financial burden of screwing up people's cars in this way. Indeed, filling your car with an oil with specifications different from the manufacturers does not invalidate your warranty as such. Only if the fault is related to the oil change (or they can prove it is such) will they not honour the repair bills. This was thanks to European consumer law that came into being over 10 years ago. However to be safe I would rather still to the manufacturers recommendations whilst the car was in warranty.

Okay, so I think I've droned on enough. In summary I think for most people it's best to stick with the recommendation in your manual, especially if in warranty. Even more so as actually you can find pretty decent oil for not much more with some internet searching. I do think though it's never good value or even any better to get servicing done by the franchised dealerships. There are plenty of independent specialist who will offer a better service for half the price. For the majority of cars (petrol) including VAG group cars, for normal driving conditions, any decent oil of the highest/latest API/ACEA grade is okay.