I've raced a tc3 for about 5 years (until this year) and never felt the need to go over to 64dp. It still has the original kimbrough spur gear in it now.
Providing the motor bolts are tight and the meshing is good then it will last for ages.
However, if you really want to fine tune your gear ratio and run 64dp just be wary outside of small stones etc that can jam up the spur gear and give you dnf's
As has been said, a 96 should be ok for most tracks, but if you know the final drive ratio of the tracks you typically race at, head over to http://gearchart.com/
and try experimenting with different spur gear sizes and see which spur gears fit the gearing bracket you're trying to achieve