Buy a set of panel trim removal tools on Amazon for less than $20. Start at the opening for the rear fuse block.
I insulated all the interior panels on my TC wagon using Thermozite (available on eBay and many other retailers). Use spray adhesive (3m or Loctite brand).
http://www.perfectfit.com/15269/154086/Carpet--Padding/Thermozite-Insulator-Padding----Sound--Heat-Solution.html
Thermozite on the door panels made a big difference in sound and door closing "feel". Very solid. Dynamat won't keep the plastic from rattling.