I am currently using Liqui Moly 10W-40 Mos2 Oil in my 1993 Porsche 911 with 100000 miles and happy with it, but I was thinking about using a Synthetic 5W-40 next change (Motul or other top Euro brand) and on top add to this oil the Liqui Moly Mos2 additive.
Since I live in Argentina most EEUU...