As far as value goes, to be quite honest with you, most of the sunroof cars I've seen are actually hurt in price by the sunroof.
For one reason or another, people just don't like to see sunroofs on their Firebirds and Trans Ams, especially with other options like T-Tops.
I've never read that anywhere or anything, but from watching eBay and other online car sales sites, that's just what I've noticed.