Anyone who has an E39 knows the sound system sucks. Heres a great way to upgrade the system by replacing the factory amp with an aftermarket amp while maintaining the factory speakers, wiring, etc... Huge sound improvement. Speakers are crystal clear, and the factory subs really have some punch to them. Works with all sounds system options in the E39. All wiring on the PCN is color coded to match the factory harness so install is straightforward.
German Audio Specialties Passive Crossover Network+ Frequency Shaping Unit-$350
Alpine PDR-V75 Amp- $375
Buy both the PCN and Amp and Ill throw in a custom rack, line out converter, DSP conversion harness, RCA cables for $650 plus shipping. The amp rack convienently places the amp and PCN in the factory location out of the way.
