Fanfaro 6719 is probably ideal base oil - I have been doing 20k intervals on it for past 100k km - motor now is 180k km - 420xd ST1 tunned ti 235hp. b47 2015car.
- oil consumption 0L
- drive 30/70 city higheay
- agressive in city, 130kmh on high way
= engine is clean! was inspected recently with a scope, master was surprised how good it was.
= never needed chain replacement, no chain sound.
PS: I never ever used any additives in oil or petrol.