RE: Hitec 55's with FMA receiver?
As I pointed out earlier, the M5 can cause your servos to buzz a little -- it's a function of its computerized decoder system.
Personally I think you took a big step backwards in settling for the Electron 6, it is a "last century" design with no real ability to reject noise or interference once it gets through to the decoder section.
Far better options would have been the Berg 5/6, the Sombra Shadow or even that M5 you sent back.
In my receiver shootout article (held up a few weeks because I've been given a "sneak peek" at a new offering from one of the cutting-edge vendors) the plain old PPM/FM receivers simply do not perform at all well when faced with any kind of noise or interference.
If you've got a "nice little amount of $$ tied up in this plane" then I suggest you should have gone for a receiver that offers you some protection against interference and (in the case of the Berg and Sombra), even some protection against being shot down by someone else on your channel.