After five years it was about time, and subjectively, it has also brought something.
Although I always fuel up a "good" (hopefully with many useful additives provided) fuel from Shell, but can not hurt the addition of Liqui Moly.
And why "subjective"? Well the reason is that my engine (Golf VI, 1.4l, 80hp) FELT runs quieter - that may now be really so, or even just because I want it so;) No matter what it takes, I'm going again pour at irregular intervals in the tank, because then I have a clear conscience and the engine determined not harm.