Hey folks, I have been lurking for a longtime and learned about the benefits of HDEO from this site. I was wondering if anyone has any knowledge or thoughts about using Royal Purple Duralec 15W-40 Synthetic in my 2005 Mercruiser 6.2 MPI? I ask because it is available near my marina at a decent price in gallon jugs. I have not heard much about RP anywhere. Let her rip ....