Replacing speakers. Anyone using boom mats?
 

I am planning to replace the four 6X8's (2 in the door/2 in the rear shelf) and the two 8' door woofers with upgraded speakers.
While I have the stockers out I was thinking of getting some boom mats to put in the openings before installing the new speakers.

Is anyone using those now?
Did they make that much of a difference to be worth buying them?
Any other suggestions?

Thanks