I've read through all of this, and i am starting to get a grasp of what you are saying. Going from what you said at the beginning of this thread, the manufacturer states that you can essentially use any oil under the moon within reason that has the API spec, considering current weather conditions. But that is not answering your questions. 1: There is no merit in seeking SPECIFIC precursor specifications to 229.5, as most, if not all of the oils that have this spec are backwards compatible. It would be the same analogy as how dexron VI is backwards compatible to dexron III and II in most transmissions. 2: You could try your hands with 0w30 and having the "same" properties, but it would be on the thinner end of the spec. Now, you have to remember that there is always some room in that spec 229.5, and since every manufacturer has different formulas in base oils, type of additive packages, and overall manufacturing, some may lean thicker end vs thinner end. However, with modern oil being so good and being made the way it is, it would essentially offer the same protection and give some gains in power and fuel economy. 3:This goes back to what i said at the end of number 2. There would be no discernible difference as long as the oil has the api spec. However, using such a thick winter weight will affect cold start wear, which accounts for 75% of total wear, due to most of that oil going to the bypass because of oil pressure on startup. That being said, you have to account for most european spec oils having to deal with an extended duration OCI, and being so, manufacturers will specifically formulate their oils with higher quality base stock, additive packages, and with that, more testing to make sure it meets the stringent specification. This in turn gets reflected back on the final price. Anyone who reads this and finds mistakes, errors, and things of note, please do not hesitate to reply. I welcome any feedback! Thanks for reading!