I bought a 2002 BMW 530i, and the factory stereo is horrible. The web consensus on the BMW boards seems to be: Keep the Alpine head unit (it is integrated into the car's display and steering wheel switches, speed/volume control, etc.) Keep the factory speakers. Replace the BMW amplifier. Add a sub. The local shop that appears competent is suggesting the above approach with following package: Eclipse PA 5422 4 channel amp for the mains Eclipse PA 4212 2 channel sub amp Eclipse 87121DVC 12" Woofer Any feedback on the approach and specifically, Eclipse equipment?