Mp3/DVD player or CarPC

[ppjawor]

Hi guys,
Im looking for some info how to upgrade my e38, 16x9 screen, audio system.
Now there is only 6discs cd changer which actually is not required anymore nowadays.
How can I convert it to mp3/dvd player or "carputer"? Is it possible (where & how), while not spending huge amounts?
Thx for ur feedback
Peter

[AsifSaif]

Everything is POSSIBLE, narrow your option, would help in replying the question.