ORIGINAL: losi101
Personnally i would change out both. If you have the 650m it's a little to slow for my liking and the regular 650 doesn't have enough torque for either the steering or the throttle/brake but is plenty fast.
I guess it depends on how much you want to spend and how competitive you want to be.
That's why I like the Ace 1015. They have a good balance of speed and torque.
Ya I would like to change them both out but I can only do one right now. Eventually both though. Thanks