Best is very difficult to have a conversation about because oil formulas are constantly changing . Without oil analysis to compare it comes down to seat of pants . Having said that I have been using Liqui Moly # 2040/2041 for several years in both Porsche's . Oil analysis has been solid . It is a 5w40 synthetic . I know Porsche now recommends a 5w50 and I believe their branded oil is a European Castrol product but I can't confirm that .
Because it is so hot here in Georgia in the summer I am thinking about going to 5w50 or 15w50 . I haven't figured out what brand yet but may use Driven . For those that don't know Driven is the result of Jake Raby/Charles Navarro/Lake Speed Jr in collaboration with Joe Gibbs racing to come up with an oil that was " better than what was available " . Ultimately use what you are comfortable with and change it often .
