1)
What is the connection of the end of the verse to the beginning?
1.
Rashi, based on Targum Yonasan in Shmuel II, 22:4: When I call and pray to him, I will thank him even before the salvation, for I trust that I will be saved from my enemies.
2.
Radak: When I pray and I call to Hashem, and I praise him with my Tehilim, then I am saved from my enemies.
3.
Malbim: At a time like this that I am not afflicted at all, I call to Hashem and call Him 'praised', for all His good acts, and through this alone I am saved, and I need not pray [for salvation] at all.