On Kunnakudi, I remember one of his yesteryear interview to DD..he was talking about greatness of Kannadasan...while composing the 'maruda malai maamuniye' song, Kunnakudi wanted to challenge Kannadasan and hence composed difficult bits but Kaviyarasu without any effort were composing the lyrics as soon as Kunnakudi finished.
Towards the end of the song, Kunnakudi was really annoyed and wanted to throw the toughest and gave the tune of the final verses and again kaviyarasu with little effort came up with the words 'kadal athu, malai athu' and everyone was dumbstruck.
Healthy competition gave us good songs then. Rare to see such healthy competition these days when the ego takes over everything.