The LS1 is in the 04 and 05 models. The LS2 is in the 06. You can't get one with the LS7. It's only in the Vettes. The M6, M12, A4 and all that are the transmissions. It seems to me that most people have the M6. The M12 (which I have) from what everyone is saying is a little more MPG friendly. That's about all I know about the transmissions. As for the motors, if you have any more questions I may be able to offer a little more help.
But the 2009 will have an LS9, a 7.5-liter, 600+HP beast. Here's why:GTO judge said:
The 2008 GTO was to have the LS7. 500 HP... That is now a pipe dream.