Steps to replace 328GTS upholstery

I would like to replace all carpet and upholstery in my car. The carpet seems to be a no brainer, not sure about upholstery. I did a search on this topic and did find a few old threads, some referenced pictures that would not display, others made reference to what a pain it was to remove the heat shield. I have a 1989 328GTS and I can see the 3 nuts that need to be removed. Seems like it would be easy to remove, is the configuration of the heat shield different for a 1989?

If anyone has tackled this project any input would be much appreciated!