myself I have never used it but a friend has and he seems to like it a lot...he used it on the "dog house" in his van ...did seem to help with the engine noise
Homeless depot sells a sticky backed product that works in exactly the same way. Might save you a fortune. It’s found in construction products in at least two roll sizes. I used it on my F150 and it’s been fantastic.
The only sound deadener I'll mess with any more is from KnuKonceptz. Stupid name, I know, but every thing they have is high-quality and reasonably priced.