Carpet replacement question.

[rs74]

I will be looking at buying some new carpet shortly and have a few questions. First of all I am thinking about using some dynamat or something similar for the base. Can you buy new carpet padding or does it come with the new carpet. Second, are you guys even putting the padding back in when new carpet goes in or not.

The reason I ask is that I took the carpet out of my 85 K30 and found the rust underneath. I threw the padding away that was on the floor pans because it was soaked. I kept the padding that is under the seat. So I am wondering if I even need to replace the pad or just put the carpet on the dynamat. What has everyone been doing when it comes to this. If you don't put the pad down then is the carpet still fitting fine?