Wow...this went from LT1 or LS1 to Mustangs....*YUCK*
Back on topic?
I say go for the LS1 M6
At first I wanted an LS1 auto- but I ended up getting an M6...after taking it down to the track...I am SOOOOO glad I got the M6 and not the auto.
Good luck with whatever you end up with.