Try this link:
Bmw 16149068988 CONSTANT PRESSURE VALVE16999914
I am not convinced yet that the problem is caused by the pressure regulator though but that's an easy and non-expensive solution.
Please let me know how it goes. Now that the weather is colder here I don't enjoy working on the car. Besides, since the engine cools off faster, this issue doesn't happen as ofter.
I am going to get a fuel pressure gauge and test the pressure with the hose pinched.