I got mine from GMpartsdirect.com,
Part No. 12495746 CD Changer $299.40
12497876 Installation Kit $72.00 (new PN)
Shipping & Handling $ 66.85
Total $438.25
I have done two so far, mine and a new found ZO6 friend's.
Took me about 2 1/2 hours for mine, took about 2 to do his.
The two pop rivets supplied with the kit that are to go in the top holes are too long, they bottom out on the rear frame cross member. I used shorter rivets, everything else went together very easily. Make sure you run the wiring harness just as explained, from rear to front, otherwise the large connector that plugs into the CD Changer won't fit under the seat belt retractor. You will see what I mean when you get the kit, and look at the difference in the sizes of the two connectors. Also, don't use paper labels on CDs if you burn your own, they cause the CD to drag when playing sometimes, this causes the CD to stop playing. Oh, one last item not covered in the CD Changer manual, the radio number 5 button changes cds.
If you have more questions, ask away.
vettepilot