Trunk Mount CD Changer ?????

Greetings fellow Vic enthusiasts. I just picked up a 99 Vic Lx from my mom. It has all the toys and my question is, the radio has a cd button but the changer was never installed. The connections are in the trunk. I have a pioneer CDX-P650 6 disc changer. Does anyone know what type of connector I need to hook it up? Also the approximate cost would be nice too if known. Thanks in advance to any and all posters that answer my questions.