The battery in my 2001 C5 died and that's okay as it was almost 3 years
old. I had a heck of a time removing the side terminals because GM left
little or no space to remove side terminals. My only small 8 mm open
end wrench slipped out of my hand and dropped in slot in the bottom of
the battery box. I got the battery out using some small vice grips.
What a dumb-ass design! To make a long story short I managed to fish
the small wrench out using a long telescoping thing with magnet on the
end.

Happiness is Wall Mart batteries! Where else can you get a battery
replaced for free on FRIDAY night. My battery was still within the 36
month warranty and they exchanged it and gave me a new one with
another 36 free replacement starting from Aug 2010.

After a very bad experience with Delco batteries, I only use Wall Mart
batteries. They are as good as most with a better warranty and they are
open 24 hours /7 days a week. Batteries seem to always die on weekends.