[rfuerst911sc]

Back in the early days of synthetic oil it was common when switching from dino to synthetic would cause leaks, some minor some severe. But that was back in the 70's and a lot has changed in regards to engine gaskets and synthetic oil. I run Brad Penn or Valvoline VR1 in 20w50 in my 1983 911SC. The technology at the time this engine was built plus the thermal expansion/contraction of the air/oil cooled engine leads me to believe a quality dino oil is the way to go. In my new to me Boxster S I will run synthetic. I'm pretty sure I will use Joe Gibbs Racing DT40 which is a 5w40 synthetic, mainly because Jake Raby recommends it. But for street driving most synthetic oils will probably be sufficient but I would never go long with change intervals, 5k max between oil/filter changes for me.