I read on another site that if you fill the stock sub with polyfill, it would give better bass. Well, my cousin and I own Armadas and we put the polyfill theory to the test. I can honestly say that it works. The bass now is not as hallow and you can feel it better now. Now it is not better than going aftermarket, but it is better than having the stock with out the polyfill. I purchased a bag of polyfill at WalMart for a $1.57. so it is a great bang for the buck mod, worth doing in my opinion.