Try a fliud change and this time use the "Honda" brand "white cap" MTF. It should help with the notchiness and smooth your shifting all round. As Kaz said, it might be time to overhaul the LSD from lack of lockup pressure but it seems WAY to soon unless the car has been floged on the track or something in its past you don't know of. Still seems to soon for all that.

Cheers
nigel