I used the 303 product on my 2000 SS Convertible and followed the directions as prescribed on the container. After applying the product and waiting the 24 hour 'non use' wait periond, I put the top down. When the top was put up, I noticed some smudge marks on the fabric. The smudging, I am certain, was a result of the 303 High Tech Fabric Guard. I was not happy with the results to say the least. After a few weeks though, the smudging faded away.
So if you are going to use the 303 High Tech Fabric Guard, be prepared for a little bit of smudging. Don't worry though, it doesn't last long.