The rx-471 also works very well with the M11x. I just switched from a futaba 3pm 2.4ghz to the M11x, such agood radio. I read and re-read so many threads about latency that I never really thought about precision. The M11x is precise!

The 451r is only useful if you plan to use the SSR compatible servos. 92744 & rx-471 are the way to go for everything else.