Originally Posted by lvlemphiz
I feel like a lower factory output Z lined up with a strong factory M5. If they were both truly stock, then how else could this be explained? maybe the Z owner is bad about maintenance and his car needs some routine stuff done to get it back to peak output. With what information we have, it should be left at this:
Possibility #1, M5 is hiding some mods
Possibility #2, The Z06 is poorly maintained
Possibility #3, M build this particular engine well, and Chevy didn't do so great with this particular Z "