I will be upgrading to commercial equipment this spring (mainly handhelds for now) and i was wondering about maintenance. I have heard some guys only use stihl oil and high octane gasoline. I was wondering if this is necessary as opposed to just buying two stroke oil from wal-mart. Would it help the equipment last longer? What are the reasons for doing this? Also I have heard of many people using the E3 spark plugs. Would this combination affect performance enough to use them? It is fairly inexpensive either way but i was just wondering if there is any major performance difference as i would like to keep my new equipment going as long as i can.