Dynomat is deffinityly worth it for the sound quality, but 800$ seems a little steep. When i got my system installed i got dynomat instaleed all around and it cost me about $450 more. Ask why it is so expensive, becasue i doubt you will use more than i did.
The sound qulaity is deffinitley better, but the biggest difference for me was how much it cut down on road noise. Im glad i did it. And im glad you decided on a system, cant wait to see pics