I have E60 but since this forum has best of best audio gurus I thought I will post here, also audio isn't much different in between these two car models.
I had simple 6 speaker stereo in my car which I upgraded to following:
Earthquake SWS-8 undeseats
Diamond Audio 343i (Coaxial) speakers in the front door replacing the stock one
Alpine tweeters in the tweeter gril above door cards
Rear parcel shelf speakers left as stock
PDX-5 hooked to run 4 channels of the speakers and 5th one to the earthquake (parallel). I had to run cables all the way back to the boot and install amp there as there aren't any spare space in the front.
Its way improved then what I had in stereo setup. Recently I retrofitted CIC/COMBOX so running all 4 channels in HiFi mode gives you full balanced signal. I got rid of LC6i which I had before converting CCC high level output to PDX5 low level input.
Now I am looking to move step forward or call it stage 2. Ideally I would like to get Logic7 with MS-8 but its too pricey for me at the moment however I will get it in next few months, I will call that stage 3. I recently bought Alpine PXE-H660 audio processor and thinking of improving my setup a bit, specially staging etc, I will use until I can afford MS-8 with full L7 setup.
Gradually I will buy things and will make a proper setup first, can't afford all in one go. First I need to get my speaker setup right. Can someone advise on my speaker setup, does it look right? I am not sure if I should have bought co-axial speakers in the first place (didn't know much, got whatever I could), if not can I still use them in the rear doors if I ever move to logic7 setup. Is mixing different brands of speakers ok, or should I simply get BMW logic7 speakers all round? I read someone say they will prefer Rainbox SLX 210 instead of BMW L7 speakers. Please suggest me better speakers which is not priced like morels, kind of value for money. I want to put them all across the car from center, all 4 doors to the rear parcel shelf and finally hook them all up to MS8/PDX.