THEE THEE is certainly the most complex song composed by him. But once he said in an interview that "Pachai Nirame" / "Saathiya" was the song which he found most difficult to compose. He said he was totally confused, and wanted to make it a fast song.. hence the punching lines 'Saakhiye / Saathiye'... But later...majority portion of the song became melodious. Another instance he said, he was in deep dilemma while composing Bombay Theme.
According to me; After Thiruda Thiruda... Rangeela was the most complex from ARR. The arrangements, the progressions, the unexpected deviations, everything was unpredictable in every song in the album! Completely unconventional pattterns, totally ground-breaking!!