Looks like the new C6 is not as great as GM marketing says.

Someone was trying to tell me last night at a club meeting that GM under rates the capabilities of their engines. Your comparison proves him wrong.

The C6 has even worse torque management then C5 did to reduce GM's costs during warranty on drivetrain repairs so without being able to fully tune the PCM and TCM you cannot make use of performance mods thus even with the C5 Z06 HP/Tq numbers the C6 is not really any better as its calibrated now.