It is way less than Dynamat and just as effective. Second, if drivetrain noise is your primary concern then the best place to start is going to be the floor. Especially the trunk area.
Realize there are two ways to stop unwanted sound. Either you can use a material which will absorb the resonating wave and basically keep it out or you can add mass and change the frequency at which it resonates. For most practical puposes the absorbing material is the most chosen method. Brown bread is really good stuff. realize however that you wil be adding weight no matter what. Do it in steps and see whats good for you. If you do the trunk area completey and possibly the area around the gas tank and shock towers, you should notice a nice decrease in interior db level. if you notice alot of noise is coming from the tranny area then you should take a day and pull the seats and do the entire floor. You will not be disappointed. For the doors, they are pretty well insulated, but you can use a combo of adhesive mat (Brown bread etc) and a foaming spray . This will practically make your car impervius to outside noise. keep in mind however that our cars have a lot of squeaks and rattle that come from the interior. these can usually only be resolved with proper lubrication and somehow changing the mass of the resonation item. hope this helps.
