Dynamat and self-adhesive

[Foot]

I am trying to get the car to have less road noise, not that it bothers me just wanted to spend some money. Also, I plan on getting a Touring muffler in the next few months. I have a 3 door hatchback.
My questions, I plan on getting 36 square feet on extreme dynamat. I believe that will be enough for my purposes. I want to get the two doors, spare tire and surrounding areas and the hatch. I do not plan on removing any carpet. I want to know would self-adhesive help to secure it to the metal. Also, should I tape the edges of Dynamat to insure it does not run the glue like material I have read some people complain of?
The other concern are the wheel wells, I see the factory already undercoated some areas. I would like to know would spraying the plastic front wells with rubberized asphalt help. Also just spraying more rubberized asphalt on the existing coating help even more.
Thank for your responses.