If you are talking about ferrite noise/beads clamps, yes they work to remove high frequency elctronic noise. The beads are really designed to stop the EMI and RFI caused by switching power circuits.
I bought dozen of many sizes for $6 and I placed one on all my chargers, power supplies. I have not placed any on my r/c cars as I use capacitors to capture the noise.
The reason why I places the beads on my power supplies is the fact in the good ole days of NIMH all my chargers were on a 32amp power supply. When one charger peaks or I turn on/off my tire true or test a new built motor it could create a large power spike or any other electronic noise. This powerspike could cause the other chargers to false peak which I have seen happen.
As for installing a ferrite bead on your power wires inside the car, it shouldn't hurt anything but could solve issues with radio interference and glitches. I use novaks trans-cap modual on all my speed controllers becuase it provides better protection from RFI and EMI that a stand alone capacitor won't.
"If everything seems under control, you're just not going fast enough." - Mario Andretti