You're my hero. And may also be my downfall. The wet duvet sound appears to be just the quality of the standard-fit speakers, possibly combined with an excess of low/midrange with the standard 6x9s - possibly why a 3-way 6x9 has been said to have such a stark improvement, in a low-hanging fruit sort of way. There's nothing covering the speakers aside from the perforated grille, and the speakers themselves are well sealed with the both the panel and door card. I'll get these 6x9s swapped in, in the next couple of weeks probably, and see how it goes. But replacing the lot in a more considered fashion is quite appealing. Don't want to spend a fortune, but it seems like around £500 could make a pretty good job of it so long as components are chosen wisely. I'm assuming the £600 DSP boxes are generally for taking things to the next level, and by no means mandatory or necessary for a basic upgrade? For sound/vibration dampening, I've got the leftovers of a large roll of Tecsound SY50 from my home AV room sound proofing I was hoping to use - all over the insides of both the door panels and the door cards. Are there any compelling reasons not to, and instead get some Dynamat or a comparable alternatives vs the Tecsound for "free"? The Tecsound is marketed for home/studio use generally, but it has the temp tolerance for use in a car, so see no reason why it wouldn't do a good job of things.