I just recently installed a pair of JL XR650CSi components, along with an amp. I was curious if I should sound deaden the door? Is the difference worth paying the $$$ for the material? I'm just figuring out if the increase in sound quality is worth the money. Also, currently I'm running the components off the amp and using the factory HU. If I later on upgrade the HU, will the SQ be better than using the factory HU hooked up to the amp (speakers get the same amount of power before and after)?

 

from what i hear it makes a huge difference, not only in quality of sound but dampens road noise extremely well

that is if you go for the quality sound deadening material like the foil backed stuff, not the rubber compound

 

Does anyone have any experience on this topic? What material is the best for the money? I would like to get several opinions if possible.