Gripey,
Jim is correct about the noise level in a Z06. Remember that the guiding design principle in the C5 Z06 was on performance, and to achieve that, wherever weight savings could be achieved, they were. You'll notice that the Z06 does not have a power antenna, for example. Nor does it come with a power passenger seat.
Regarding the trunk area, it is open to the passenger compartment (there are aftermarket companies that sell partitions), and when Jim says that a lot of the cabin noise originates from the bulkhead behind the seats, in my experience, he's absolutely right. In my old '03 Z06, I also had Borla stingers, and occasionally I'd get this third gear drone that was loud enough to drown out the radio.
Still, for seat of the pants performance, a C5 Z06 goes like a rocket.