I've followed many threads on LS regarding 2 cycle oils. Many use Amsoil, others use Opti-2. In many cases, "...I use xxx" but without stating mix ratios. I am supposing many of those posts mean 100:1. I've used Amsoil in the past couple of years for my 2 cycle Stihl products, at 100:1, or 80:1. I've also used 100:1 in an old LawnBoy (pre-DuraForce era) -- finally able to keep exhaust ports open. I also have a LB DuraForce, but it failed after 400 hours, using LB oil. For the last three months of the season, after a rebuild, I used Stihl 32:1, but that proved to be wrong. I was so concerned about another failure. However, the Stihl oil is not ashless, and the buildup was bad on plugs, exhaust, etc. I wanted to try something different this season. I also use Stihl 50:1 in a 5.5hp Sizuki on a Toro Proline, but it gets pretty dirty too. I want to find something cleaner. I ordered two bottles of Opt-2 oil, and find the suggested mix is 100:1 (their web site says nothing about mix ratios). Reading many posts on LS, I was expecting 50:1 as "normal." After buying two bottles from mail order (never have seen it any dealer in this area - no clue where to buy locally), I now realize a huge price difference between Opti-2 and Amsoil. At 100:1, for a 5 gal mix (oil only): Opti-2, 1 gal pouches, $5.93 2.5 gal pouches, $4.06 34 oz bottle, $2.82 Amsoil, 32 oz bottle, $1.59 Is this right? Obviously, for richer mixtures, the prices go even higher. I'll spare you the arithmetic, but can provide by PM if anybody is interested. I'm thinking of running the LB DuraForce at about 75:1 -- I've lost it one time, and don't want to loose it again, and maybe the Sizuki at the same ratio. I know my Stihl gear has done well with Amsoil at 100:1 or 80:1 (most of last season).