premium grade gas should be run in ALL saws. small or big regular grade is just not acceptable unless you want to aid in murdering it.
my proof? i was on a job with a Husky 181, with my gas it ran great.. but on this job i ran out and used a friends fuel, 50:1 mix with cheap regular grade.. 181 vibrated so bad, sounded like hell and was pretty low on power.. i managed to finish the job and dumped the fuel and refilled with my own fuel at home and the saw ran just fine again. why risk your saw skimping on fuel?
if you look at it another way, if i was doing a removal on a large tree and my saw was acting that gutless on cheap fuel i am risking my life trying to baby the saw through a big cut, wondering when its going to stall as the tree goes the wrong way because i was not able to pay proper attention to the tree.. too busy keeping my saw running!
with prem gas my full power is available, and i could make a clean cut and get the tree down in the marks i set. when it comes to felling trees.. your life is in your saws hands.. now with that perspective is it really worth it?