The manual and the sticker on the car are 20 years old. MB changed the recommendation to 5W40 in 2010. Fifteen years ago, months after I bought my first Crossfire.

You can use ANY oil on this list, but notice that it leans, now, to 5W40 and 10W40. MB has moved to heavier weights to protect against engine wear.
For areas of cold (outdoor temps below perhaps 40-45F) where you start the engine COLD a lot, I'd go with 0W40. But living in Texas there is no way I'd put that stuff in my engine.
Put an oil pressure gauge on the engine and you will see why I say that.

https://operatingfluids.mercedes-benz.com/sheet/229.3