[drubrew]

So you are wasting one of your channels on the - Alpine PDX-5 amplifier, correct. Do you have the coupe or Sedan? I have the 08, M3, Sedan. I swapped all my speakers for Bavarian Soundwerks with the DIRAC setup. Should I parallel the rear doors with rear deck? Even though the rear deck has tweets and Mids and the rear doors only have mids? I have not changed the under seat subs yet and have not decided on the trunk sub yet. May do the JL Stealth box unless you feel what you used might be superior?

Do you have back up sensors and GPS? I have been struggling with how to interface a system and cant decide between the Alpine you are using vs Mobridge. The iPod interface under the middle arm rest is god awful and if I use one of the extra digital inputs on the Alpine for my iPod then I loose GPS and backup sensor voicing. I have a way to pull digital from an iPod/iPhone and still send USB data for controls through the stock system. As this will be my primary source. With Mobridge there is only one digital input unless I splurge for the iPod interface too. But the price of doing Mobridge and DSP etc etc will be so much higher than the Alpine.