I went through this whole debate last year.
I'm really glad I got the automatic. I'm impressed.
I've always driven Manual, Including a 96 Z28+SS, up till I got the 06 MC SS, didn't come in Manual.
The ZL1 A6 works great. Love the PTM's and the paddles if/when I want to play.
I'm also glad I went for the Navigation and Sunroof. No Regrets.