Excellent post again App!. Yes, trendsetter song in TFM. Very innovative and unusual composition from Thalaivar, especially the mridangam. Added to the first interlude masterpice as you mentioned, I would bet on the extra-ordinary prelude and for the most unusual thinking in the history of film music. Mridangam for the love song.
http://www.youtube.com/watch?v=E8fVGq-OxxU
You might have watched this video which is quite old, but hear what his mridangist (don't know his name) have to say about the prelude. 'Aniyaama Akaramama use panninaru' and see SPB's face when he says this. What a proud moment for anyone, when someone speaks high of his best friend. Kannu kalagirichu, a moment of pride for all Raja fans.