I purchased some dynomat and installed in the rear fender and floor of the cargo area. Seemed to help reduce noise from the exhaust entering the cabin. I would have liked to do something with the hatch but it has too many braces between the outside sheet metal and inside to install material like dynomat.
One thing I did notice as well which I have yet to take care of is the outside sheet metal on the hatch has detached from the braces. The factory has what looks like expanding foam attach the inside braces to the outside sheet metal, appr.. 1/2 thick, which has broken loose. Trying to decide what to glue it back together with that will hold up yet allow for flex and wide temp fluctuations.