So much fail in this thread.
Firstly, the shift kit doesn't fix the inherent issues with the transmission controller, that is the source of all the things you are complaining about. Every time it clunks into gear you are flooring it right? but the electronic throttle hasn't opened yet... It waits till it gets the signal from the auto computer before it winds the throttle on. If the throttle had instant response you wouldn't be having issues at all.
Disconnecting the battery won't do anything, other than reset the radio.
Perhaps you should have researched before you jumped into the shift kit. Are you sure the 'specialist' used Nissan MaticJ or similar? Most just stick Dextron3 in and fluck the box, knowing you will be back for a rebuild.
Finally, stop driving in D, it's for grandma...