Currently, the computer-in-car is in the development phase. I am amassing hardware at this point. So far, here's what I've got going into it:

    Model Price Purchased From
Stereo Group: Head unit: Pioneer DEH-P7000R $239.00 www.smilephotovideo.com
  Subwoofers: Infinity Beta 12s $440.00 Some guy
  Sub amp: Kenwood PS200 $50.00 Cash desperate friend
  Main speaker amp: Alpine 3527V Dunno Local stereo shop
  Capacitors Cornell-Dublier 20V .5F x2 $35.00 www.partsexpress.com
         
Computer Group: Display unit: Icom IC-2800H (2M/70CM) $528.00 www.aesham.com
    3" TFT LCD 480x234    
  Keyboard Dauphin (about 8"x5") $15.00 www.gatewayelex.com
  Mouse Alps Glidepoint $11.00 Ebay
  Joystick Gravis Gamepad Dunno Wal-Mart (5 years ago)
  Sound card Gravis Ultrasound MAX $20.50 Ebay
  Video Card ATI XPert@Play 98 $20 Ebay
         
Stuff I need: Head unit AUX input: Pioneer CD-RB10 ???  
  Computer: Pentium 266-350 ???  
  Power supply: DC 250 (12 V) $145.00 www.quantumpower.com
  Hard drive: 40GB ??? ???

Software:

(Dos) MPXPlay