robot servos are made for 7.4V who knows how they would perform on standard 5/6 V in cars also they have bigger operational angle (of course EPA solves this)
also the might have some gears nylon and in big truck you should aim for all (really all) metal gears
Radek
V4 D8 - RX8, XERUN 4168SD
F1-09 - Tekin RS Pro, 17.5t Redline, 2S LiPo
Sakura Zero S - LRP, Saturn 20T, 2S LiPo
*EX-10 Eurus*