How can i modify the radio unit? I heard that the original nav radio not only lowers the volume, it also cut's off frequencies lower than 40hz at high volume, so an audiocontrol lc2i line out converter wouldn't help with it's accubass feature. Originally in my harman kardon setup, there is a dedicated wires for subwoofer coming from the radio unit to HK amplifier then from HK amp to factory subwoofers. I tapped into the wires prior HK amp, took off the factory subwoofers, installed aftermarket amp and sub.
I was searching for an alternative and tho the Dynavin and it's clone look good, they both have technical issues, specially the sound quality is considerably worse than the original unit. Other aftermarket units like pioneer have huge advantage over sound quality and i would consider one, but they look much worse than the original when installed in the car.
If i could modify the original nav radio unit to stop it's factory setting of rolling off bass i'd be more than happy.