[adhrp]

Well, that article mentions it is for motorcycles although it is applicable to all 4 cylinder engines. I broke-in my motorcycle the "hard" way and it runs just fine and has had no issues. I also broke-in my Highlander (although it is a V6) by driving how I wanted and it runs amazingly smooth as well. I also get above average gas mileage from it. For both vehicles I let the engine warm up first.

As for my 328i, I bought it preowned so I don't know how it was broken in, but being a dealer vehicle I assume it was also the "hard" way. This car also works like a champ and you can click my Fuelly for gas mileage details, which are pretty impressive.

So IME hard break-in is fine. None of these vehicles are yet over 50k miles but I do not think any issues would arise as a result of the "hard" break-in method.