[Potatohead]

I set it to -6db after reading your comment. Which by the way, thank you. I'm sure it saved me the hassle of trial and error and popping out my door panels again! I also deadened the surrounding mid woofer area too.

They do sound so much better already (what a stock BMW system ought to have been in the first place). The stock BASE speakers are clearly no match even for the integral amp.

I have DAB but don't use it. I've got the system hooked with a loaded up IPOD classic 160GB. One thing I did notice straight away is that the system now highlights the bad or lower bitrate MP3s I have and good tracks now sound brilliant.

I might just leave out the amp. A whole lot of effort for marginal gain. I'm so glad I upgraded.