Once again I find Matt and I are in agreement! More problems like this are caused by cheap, power-hungry servos than any of the good, low-cost speedo and motor kit.
I run 12th scale where the radio kit is crammed closer than any other class and yet we rarely have any trouble. The key difference is that we need a small, highly accurate and reliable servo and our class is dominated by the best servos that cost more.
This is a class where Futaba and JR servos dominate because... they are small, reliable and accurate with low current draws. They are relatively expensive compared to the rest, but they last a lifetime. My Futaba 9602 servos (now replaced as my 2.4 radio needs a digital servo - Futaba 9650 now installed!) are still perfect after more than 20 years in a 12th car.
Servos are one area where you really do get what you pay for. Pay more, pay once, get the best performance and never buy one again - unless the radio gear changes!!
HTH
