No Sonny wasn't the underboss. Really there was no underboss. Tom was consigliere, Sonny was the heir apparent.

"Io sono stanco, sono imbigliato, and I wan't everyone here to know, there ain't gonna be no trouble from me..Don Corleone..Cicc' a port!"

"I stood in the courtroom like a fool."

"I am Constanza: Lord of the idiots."