"Romulan Agitato" puzzles me. The last few moments of it are familiar, but the rest doesn't sound like something I've heard before. Was this cue only partially used in the episode, or were the early portions buried under sound effects or something?
It's curious that you don't recognize it. While it's not used in "Balance of Terror" it was previously released on one of the "Best of" albums from GNP years ago.
It also turned up in "The Alternative Factor".