I use Walmart Super Tech synthetic oil for nearly all my vehicles and have for years.
Prior to Super Tech I used Castrol dyno and Oreillys synthetic in everything.
My 911SC gets Rotella 15W40
My old dirt race car got O'Reillys 20w50
I have never had an oil related engine failure in any of my vehicles with many going past 200k miles. I also only change oil when manual says to but have gone over many times.
