Multi Vehicle Sound Deadening Ideas?

Greetings!

Our dealership always tries to use new tactics and include exciting features to engage more clients and this time, we are thinking to offer the sound deading feature for pre-owned vehicles. In this regard, we have purchased a variety of vehicles from the dealership-only auction and now, willing to buy sound deadening mats and other materials etc. 

Usually, we use Dynamat, but after reading car sound deadening material review from here, we are thinking to include more brands like FatMat Self-Adhesive and Noico Car Sound Deadening Mat due to their easy application. Yes, we are not hiring experts in this, and probably, our dealership workers will perform this activity their own. 

Do you think it will be the right strategy if we apply our own? Secondly, as we are going to apply deadening material on multi types of vehicles like trucks, SUV etc. so can you recommend any sound deadening material which will fit for all of them?

Waiting for your responses.