I have flown both the 61fx and the 65 la. The 65 la is a very good engine. Being a bushing engine it sounds a litttle weak at idle but is a very powerful engine at full throttle. The 61fx is smoother and powerful to about 40 dollars smoother. I fly my 4 star 60 with a g90 supertigre. Great vertical. Needs adjusting frequently. The 65 la will fly a 4 star 60 just fine But a g90 supertigre will make it alot more fun.