So I have to come clean here. I bought a new MS290 this year and used premium fuel with Poulan synthetic 2 stroke oil at 40:1 in it. The owner's manual wants stihl 2 stroke oil (of course) at 50:1. I know some people get pretty religious about lube oil and brands and such but what is your opinion on the oil to use? I've gone through many quarts of the poulan synthetic premix over the years and never had an issue, I rather like it. Is it really that important to use stihl oil? Is it really that important to use 50:1 vs. 40:1? What do you use in your stihl?