Mini35,
TAO3 ball diff is similar to the Manta Ray just weighs less and has a thinner gear part. It is the same as the Manta ray not adjustable from the outside. I loctite the screw before placing in the car.
tamiyarcracer does have a good point. A cheap servo and servo saver will cause much misery in mini racing. I have had a car that would not track straight at all, it came back to the servo and servo saver. I now only run fast servo's in my cars and good servo savers.
I would not give up on the MO5, I have found with the right setup the car is stable and fast.
Regards,
Calvin.