Thanks for the information. Just changed my oil for the first time at 2700 miles (sent a sample to Blackstone) and decided to put the factory 0w-20 after I was not able to get the 5w-30 weight oil I wanted (Shell Helix Ultra) quickly enough, due to an upcoming track day and needing to get the job done. I'm thinking the same as you - I'll switch to the Shell at 5k miles and run it from there. Man, I had a '99 M3 - bought it new and owned it for 5 years. I very much miss that car... it was so fun. Selling it was one of the dumbest decisions I've ever made (my life is boring).So this thread really made me question the 0w-20. I'm at about 4k miles changed the original factory oil a few hundred miles ago and was going to go 3k (7k total miles)to change again to 0w20.
So I reached out to a friend of mine who owns a shop working on BMWs and has been in the business for 20 years and is just a very smart and reputable individual. I asked him his thoughts on the 0w-20 and he said in hot weather when you're pushing the car is just not thick enough. Take that for what you will, I'm just a guy on the internet who knows a guy...but IMO that was the gospel. I will let this 0w-20 sit in the car until I hit 5k and will be switching to 5w-30 every 3k moving forward.
Will likely be using the full synthetic gold bottle Castrol 5quart jugs they sell at Walmart. Used that stuff for 8 years in my old M3 and it ran like a top until the day I sold it to someone who is own their third track season with it.