I have a TF Cessna that had some problems with the wing servos. It was straight radio noise - not engine related. THe buffers worked very well - but are expensive when you need to do multiple channels.

I'm going to try out using ferrite beads on my first gasser this week. It was getting hit, just at certain times/locations during the flight. turned out to only happen at certain orientations wrt the transmitter and only with the engine running. We'll see how that goes.