I'm not sure why some folks are pushing this post in an unnecessary direction. Let's stay on topic here. This is about the best choice for GDI engines knowing what we know NOW.
With that said, based on the Afton Study Gokhan shared we know the following:
1. Base oil quality
2. Sulfated Ash level
3. Noack
When looking for an oil that will only help reduce intake valve deposits you want to consider those 3 things, with the first 2 being of most importance.
I've based my oil decision on those 3 things and have found that:
Mobil 1 AP/EP, Vavoline and Driven are the top 3. See my first post. Driven doesn't officially meet any API specs but is arguably the best of the bunch.
I'm not sure what is so hard to understand about all this.
*Dwight, the only thing about the Castrol oil I don't like is the SA level of 1.0. Mobil 1 is .8.
Keep in mind there are always tradeoffs with formulations. This is strictly focused on GDI ENGINES.
Gokhan is pushing it to irrelevant direction. Noack is valuable parameter, and actually I like to pay attention to that a lot. But what matters is final product. That is it. I mentioned Euro oils because they have approval process unlike many other manufacturers. It is not all about Noack (and it is much more complex than just base stocks as many ils with better base stocks have higehr Noack value than those with what suppose to be lower quality base stock. Mobil1 ESP Formula 5W30 which is discontinued is prime example). SAPS issue is known among Euro engines for a long time, and DI engines in VW vehicles had that issue like 15 years ago. There are numerous studies about how much oil helps with CBU and Lubrizol did that loooooooong time ago where they determined that difference between VW 504.00/507.00 oil and VW502.00 oil can be 167% more deposits using VW502.00. Also, PCV system is extremely relevant when one talks about CBU.
But ultimately, what matters for customer is what kind of approval process oil went through. This subject is discussed in Euro section for more than 10 years, and if you really want detailed information, go there, you will have more than enough.
If you want best oils, you have to go Euro oil route, but then you will have to pay often more.