For what vehicle bro? My opinion is, no, you can't have too much speed. You can dial speed out with most radios if you need to. I like very fast servos and I never dial speed out. My steering hand is all of the control I need. On the other hand, for an inexperienced driver who doesn't have that kind of control over himself, speed will only hurt him. The slowest servos I run are .08 sec. and they get faster from there.