Well this is weird. I have been using Royal Purple (and to a lesser extent Mobil1 HM, another SL rated oil) for a while and have had great experiences with it. This truck runs as quiet as ever and makes a minimum amount of noise. It also runs smooth as silk, gets better gas mileage, has less metal particles on my magnetic drain plug and stands up better to frequent cranking. When I went to Pep Boys on Thursday to buy the oil for my upcoming oil change this weekend, I discovered not only a new bottle, but the API Starburst and I thought "Oh no. Don't tell me the environmentalist (curse word deleted) finally got to Royal Purple and forced them to go SN and DEXOS!!!". Sure enough, the bottle says SN. They also got rid of the Synerlec that Royal Purple is known for (but they still have it in their non-API rated racing oils). I didn't buy it. Mobil1 was at almost the same inflated price, so I left Pep Boys without buying the oil from there since if I wanted Mobil1 HM, which is still SL, I would go to Walmart and get the 5qt jug for a much cheaper price. I decided to go to Walmart (the largest one in the US and the only one around that has Royal Purple oil and AC Delco filters (but I don't use AC Delco since it is now as good as FRAM) and not only found out they have Royal Purple in stock, BUT IT IS THE OLD ONE WITH THE SL RATING AND SYNERLEC! Plus it was cheaper than Pep Boys or Advance Auto. I bought 5 quarts. Then the next day I went to Napa and got a Napa Gold filter (my preferred filter other than Royal Purple's own filters when I got this current one as part of an oil change promotion at Pep Boys. Great filter at a economical price. Actually was $2 cheaper this time than last time for the same filter. Weird. I hope it is the same quality!). So looks like the regular well made Royal Purple oil with ZDDP and Synerlec and an API SL rating that is made for normal vehicles that I can find at a discount someplace is now a thing of the past and if I wanted the same oil, I would have to shell out for the HPS version with Synerlec and zinc. Now it is just a synthetic oil with some additives and a well known name that make it API SN and DEXOS specs that might not be the best as the old version for older engines. If that is the case, Mobil1 (regular, HM and ESP) looks like a more attractive option since they have 5qt jugs with better specs for older vehicles than the current Mobil1 that work better.