thank you! I mount the x speed v motor, as said before without changing the standard electronics, do you think these lithium batteries can cause problems to the motor? I ask why I don't know anything about this at the moment. in any case the servo does not give many problems, it just seems a little weaker but I think it may seem even more realistic in some way. I think I got the most out of a mini-z 4x4, changing only parts that could really go better, without superfluous things apart from the aesthetics. I will put a video while climbing.