Good Day All

Is there info or a post regarding best methods for sound deadening or sound proofing Sierra / sapphires?

Sound Deadening Material

I have a bare shell that's been newly painted and want to install new sound dampening / deadening materials

I've removed all the old crusty material before I had it painted and want to apply some new materials

I've sourced a supplier locally that can assist me with my requirements

Factory Underlay

I've kept the factory underlay and carpeting. The factory underlay is in a bit of a state. Is there a way to repair this underlay (black hard liner with the soft material underneath) some parts of the underlay are cracking, torn and breaking. Is there a specific tape or patch I could use to repair this?

What are some of the installs you may have done could assist me to do this correctly?