RE: servo extensions, ferrite rings & signal amplifier
It is highly doubtful that ferrite beads or twisting will do any good. The twisting won't hurt anything though the ferrite beads might. The two most important things are 1:good gold plated connections and 2: adequate gage wire, at least 22 gage 20 preferable. Minimise any connectors, i.e. don't insert extensions with the added connectors, solder in adequate length wire by breaking in between the present connector and servo and splicing in an extension by soldering in the wires. Hidden connectors have been the cause of many model demise as they corrode and become high impedance connections with time when not repeatedly excercised to keep the corrosion worn off.