RE: Internal setup for AMA 424 racer
Put a mechanical filter in the throttle link if you are worried about vibration to the servo. All this consists of is a weight about an inch ahead of the servo. In this case a wheel collar connecting the short piece of music wire to the cable that goes to the engine. Do the forward end as Daven said.
Here is a photo as used on all my models. Throttle servo is lower left.