Battery specs dependant on a few things.
HI there,
Under normal circumstances, like C5, there would be only 2. But in this case, you do have options.
If you were to look at 2005, this was the first year of C6, this particular battery was an 86 class battery rated at 110 reserve capacity and 500 CCA
2006, due to remote mounted battery, the size had to shrink to a 90 class battery and 95 reserve capacity and 600 CCA
And then in 2008, it changed to a 110 reserve capacity and 590 CCA. And it stayed there.
It is my opinion, based on what I have seen in the service field, that a better reserve capacity is still a better course of action when replacing the batteries in C6.
The milliamp usage for electricity in C6 is NO MORE THAN 20 milliamps.
Now, remember that Corvette is not engineered to be stored for sustained periods of time, however c6 should be able to last 21 days without issues.
My suggestion across the entire c6 product line would be the 90 PS with 100 reserve capacity from 2006-2013 2005 would be the 86 PS with 110 reserve capacity.
Allthebest, Paul