Well having read a little more and trying to gain some knowledge (very dangerous), I have the following question. Would love to build a DIY sub at one stage, however was just wondering if replacing the driver in my current sub would make any real difference or is it a complete waste of time? I don't recall the model at this time, however it is a Fidek brand sub, so lets say it's very low end, and it uses an 8" driver, 100W amp. If I was to replace the driver with a far better spec'd one would this be worth the effort (minimal effort obviously). Or if I replaced it with a 10" driver is this completely throwing the existing "design" out, and would make the thing sound worse? I'll say at this time also that it isn't too bad, although may distort somewhat under some conditions.