Originally Posted by stiltskin
The 9550 is a very smooth servo. I run it in all my touring cars. I've run the KO2413 before and it is also a very good servo, but it was not as smooth as the 9550 and was just a little "edgy" for my tastes. I haven't tried the 9551 or the BLS451 yet, but I'm sure that they are both great servos. You can't go wrong with any of the 4.
Sometimes a car or racer cannot utilise the faster speeds of a servo, and that's where the 9550/9551 goes +1, it doesnt usually need to be slowed down to make the car more drivable.
Some faster servos can make the car feel too twitchy on hard cornering if the car isnt dialled in right, or the racer can't get used the speed of a high torque/speed servo.
At a much higher level of competition, most guys can make the car perform well with the highest speed/touque servos though, so it's not an issue...