I know that this an old thread, but this write-up looks awesome. Thanks for this. I'm going to do this soon.
You're welcome. its not as good as the new trucks but really helped a lot. I notice it most after I ride in untreated 2006-2008 trucks.
Im going to add some sound dampner to the roof at some point. That should take care of the ringing from the rain and help a little bit with general road noise.
The other thing I would recommend is some deadening foam over the damper on the back walls of the cab. That fiber molded siding helps but I can still hear some noise from the back.
I just finished putting about 30 sq ft of damper (and some foam)in the trunk and back floorboard of the Focus (2002) and it made a HUGE difference. Dropped my noise floor from 3-7 db at 1k + frequencies. You can actually have a normal conversation in there now.