Ken
Gone but not forgotten
Corvette Magazine Online has a good article for removing sunvisors on a C4. I recently went through this when I removed mine. It was with some trepidaton that I removed 'em; I couldn't find an in-depth description in the GM service manual or the Hayne's book, and I was worried about the tension on the spring underneath the retainer. This article explains it all - except that I don't think you can save the clips that hold the retainer; just get new ones. 
Check out the article:
http://www.corvettemagazine.com/2001/February/visor/visorpg1.asp
Check out the article:
http://www.corvettemagazine.com/2001/February/visor/visorpg1.asp
