My subwoofer started rattling and according to this site it seems like a common problem potentially related to the Amp next to the subwoofer getting loose. It looks like getting to the amp is quite a tedious work, so I am going to have a mechanic to do that. Depending on the cause of the rattle he will either tighten the Amp mount or disconnect the subwoofer if it is no longer functional. My question is - since I am going to pay to open the back panels anyway, is it worth replacing the amp and the subwoofer all together? Would this replacement alone improve the quality of the sound with the existing speakers? Can this be achieved with a combined cost of the new sub and amp under $500 (not including installation cost)? What brand would you recommend for the amp and the sub which is readily available to purchase in Canada (again, under $500 if possible, note that I haven't done any research on the current prices for these items). Appreciate any advice from those who are into upgrading the audio on Montero. I like good sound but I am completely out of date with modern equipment.