I bought a DA 50cc for my Katana and have 34 flights on it now. I bought the engine in January, 2005. This one I think has the update with the fuel line. Its been running fine. I have 3 1/4 gallons through it, and the only "querk" I have with it is @ 32:1 with 91 octane shell gas, there is some pinging at WOT. The engine has full power on the up lines for a slightly rich setting, and I know its not overheating. My theory is its the gas. I know it is not recommended, but I added the correct amount of 104 octane boost for one gallon of gas which is .8 ounces or 4/5 of an ounce to see if the pinging would stops sence the timing is controled by the box. The engine ran fine, But, the one flight, that I got in yesterday, was with some other guy in the air sceaming his 33%cap 232 with a DA 100 at WOT. In additon to the wind, it was too loud for me to hear my own engine, so I could'nt here if the pinging went away. Now it raining. maybe tomorrow.