its ferrite rings, you will loop signal cable around this its suppress parasitic noise.
http://en.wikipedia.org/wiki/Ferrite_bead
Its not magnet but made from same material.
Yes its hels a lot!
Do not put your Receiver close to ESC and Phase wires, also try keep UBEC also away, use ferrite rings and loop signal cable around this. I most of cases it helps.
I think nothink is decide, quark not even close to MMM specs and have heat issues no any advantage IMHO maybe only one smooth start, but who knows...