The GT500 weighs some 800 pounds more than the C6. That's a lot - that's the rough equivalent of giving up 80rwhp. So, even though the GT500 has 100 more (rated flywheel) HP, it seems like it needs every bit of it just to remain on a even performance playing field with the C6.
Thanks for posting up the prices of the C6 and the GT500. Seems like I was right - they are in the same class. If that's true, then, well, the C6 Z06 isn't in the same class, is it? So, it's not fair to say, "Well, the C6 Z06 will spank the GT500, but give me the extra money that you'd spend on the cost of the C6 Z06 to mod the GT500 and I'll destroy the C6 Z06." My reasoning? Well, because, if you use the rationale we're establishing (e.g., that the GT500 is more in the class of the standard C6), then you'd have to say that the C6 Z06 is actually in a class above the GT500 and competes with the Ford GT. And, if that's the case, then you could turn around and use the same argument: "Yeah, well, the Ford GT may beat the C6 Z06 stock for stock, but give me all the extra cash that the GT costs to mod the Z06 and watch me walk all over the GT."
BTW, I don't think the performance of the C6 Z06 and the Ford GT are too far apart.