I just got my car tuned with unitronic stage 2. When I first drove it after the tune the power was impressive. It was tuned when 92 gas. I then put 93 in the next day and the power seems to be less. Also will at battery reset help/ get rid of the tune

 

You shouldn't really notice a difference between 92 and 93 octane. Maybe it was just in head?

Also, disconnecting your battery will not reset your tune. Your ECU has had it's "memory" reprogrammed semi-permanently (it needs to be re-flashed to change).