well i have a evo 40 i did have to remove the limiters but after a good break-in period it runs great . i found that when it was sputtering at wot i switched to 30% heli fuel and re adjusted and a os8 gp that took the tendency of it beeing at wot for a minnute and then die out of it. another tip is dont give up on the tuning with this eng one little click made a bigg diferance further more mine was way rich on the bottom part of hte reason for the heli is cuz i was flying at 20degF and colder