The below CD changer installation instruction is written specifically for the Porsche 993 model using the factory CD changer mounting bracket.  Aftermarket CD changer installation may differ.

Below diagram shows the exact measurement and placement of the holes to drill for the CD changer bracket.  The factory shop manual calls for the use of rivets to secure the bracket for mounting the CD changer, but self tapping screws will work equally well.  Use the CD changer mounting bracket to reference the pilot hole and drill the correct hole size according to the size of the self tapping screw you will be using.  Do not mount the bracket at this time.  

CD Changer bracket part number 993 645 221 00 

Drill a 20 mm diameter hole at the right side wirewall for routing of connecting wire.  Route the data cable through the firewall and install the supplied grummet.  Connect the one end of the data cable to the back of the radio.  To remove the factory radio please consult the following DIY. How to remove the radio

Data cable part number is 993 645 453 00

  

Mount CD change to the CD changer bracket with the correct mounting bolts and washers.  Please the data cable into the CD changer and mount the CD changer + bracket combo on the pre drilled hole.

Mounting bolt part number 900 075 440 07 X 4
Washer part number 900 151 006 02 x 4