I installed the following into my D40:
- Alpine Double Din DVD Head unit - touch screen, BT audio, hands free, DVD, ipod/hard drive setup in glove box with movies/music.
- Alpine R Type Splits in front doors
- Alpine R Type 6 1/2's in rear doors
- Alpine R Type 12" Sub in Alpine ported box behind passenger seat with passenger side rear seat in upright position (never have 5 people in my Nav anyways)
- Alpine PDX-F6 4 cha. amp running front and rear speakers
- Alpine PDX-M6 Mono running my sub
Overall, the sound system is a bit overkill but boy does it make some crystal clear sound with very powerful bass notes.
The Alpine PDX range of amplifiers are seriously an amazing product for their size. With some time spent tuning and dialing it all in is where the most gains can be had. All of the above setup poorly will not be impressive.