Thank you. I didn't know that either. I have used Castrol forever on my BMW's and I like it but didn't think to use it on the Mercedes. Is this the one??
Yes, that's the one. Not all Castrol Edge is Group IV oil, but the 0W-40 A3/B4 is the good stuff. Stock up at Walmart.
I used to use Liqui Moly Leichtlauf High Tech 5w-40 but the Castrol Edge 0W-40 is the best bang for the buck out there, and it's hard to beat for the price.