I have a Polk psw-350, that for a low-end product does ok, I have to admit I probably push it way too hard though. My question is: Has anyone ever replaced the existing woofer with a different woofer? The woofer is rated a wopping 38Hz on the low end(which of course is questionable) while some woofers that are manufactured for car audio, made by Polk and others, are rated as low as 18Hz. I know that there are different types of woofers for different enclosures, but would I be able to use one of these in the Polk enclosure after matching the specs? The Polk has a nice tone but rattles pitifully whenever real low freqs are around. I can barely watch Fight Club, and the THX logo at the opening of Phantom Menence is correctly named the sub-woofer killer. Any help or info is greatly appreciated!!!!