I use this oil in my 911 and its a very popular oil in the Porsche community, especially the track guys as they prefer it over M1 and Castrol. It does meet the requirements of some of the German auto manufacturers. Ive gone back and forth with this and M1 0w-40 with no issues. Havent tried it in my 328 yet, but plan to on my next oil change.
You might want to try the bob is the oil guy website for more information on it if your into things such as viscosity, pour point, ball bearing tests etc etc