Serpent's r&d dep. have created a document to outline the issues around modern servo's in todays 1/8 offroad racing conditions.
Offroad cars have progressed and so have rc offroad tracks and servo's.
We have made a document to give some advice on the use of servo's in your offroad car, be it the Serpent Cobra, or any other 1/8 offroad car. Use it to your benefit !
http://serpent.com/product/600001/downloads/
name: SPT Tech-tip Servo's in 1/8 offroad
Team Serpent