Nice write-up - I wanted to do one of my own install (similar to yours except for Alpine amp and different rear deck speakers). But I haven't finalized the amp bracket and settings.
Speaking of amp settings, would you mind sharing:
1. Front and rear crossover jumper settings
2. Amp gain/crossover/filter settings
3. Any set-up methodology or tools, if you've used any
I've almost finalized my settings - almost.
Where are you located in MD? I'd love to listen to your setup...
2009 E90 M3 ED
2014 X1 28i