Rob,
GET OVER IT, my friend!!!
You sold your C5 for a bite at the forbidden apple. You
cannot compare these two cars. Sure, on paper, you can compare numbers, but the cars are not even vaguely close in driving experience. I don't have extensive experience with the C5, but I have driven them and watched them race (both autox and open track). If you keep expecting that big block Cobra to be anything like your 'Vette, you're really going to hate the Cobra and be very disappointed. As has been said, the 'Vette is easy to drive up to 97% of its' limits. The Cobra takes tremendous skill to drive above 80% of its' limits. With that motor your sticking in there (which is really sharp), it just will not handle like the 'Vette in any way, shape or form. Once your tires hook up, you should be faster in a straight line. But always remember the 'Vette is plush compared to the Cobra. The Cobra is twitchy, unforgiving and a brute, but more fun than you can know.
Many times in my open track runs I have found myself behind a C5 'Vette. I do pretty well to keep on their tail. I can get a fairly decent view of the driver and a perfect view of the car. I rarely see the driver fighting the wheel or see the car twitch too much. Meanwhile, I'm working hard to keep the Cobra pointed in the right direction. I'll be the first to admit that part of that is driver skill (I'm good, but still have a ton to learn), and part of it is suspension set up (mine still needs work). But it's just a totally different car.
The other thing to keep in mind is that unless you ever put that thing on the race track, you may never really push hard enough to really get that last 20% of handling out of the Cobra, so it shouldn't be a problem for you. The Cobra should handle fine for speeds you encounter on the street, so long as you respect the car. You NEED to come autox'ing, since you are so interested in handling. I'll show you what the Cobra can and can't do (not that I'm the best expert in the world, but I can try).
Steve