Glad to see you saved the engine. I can see where you are coming from that certain manufacturer's additive packages may chemically clash. I personally have been using Mobil 1 now for over 15 years with excellent results. I pretty much always buy new as I don't want other people's problems, and I can tell you that I have not added oil to any of my cars in that time. Also, I worked in the quick lube industry for ~8 years and I can say that MOST of the lube techs that quick lubes hire are ROTTEN. I will never use a quick lube again as I don't want idiotic monkeys working on my car. As long as I am physically capable I will change my oil myself. Once I get to the point where I am no longer physically capable, I will take my vehicle to a mechanic that is skilled.