hi new to the stereo part of the crossfire i am looking at hooking up my monoblock amp and one of my 12 inch infinity subs but i want to keep the stock cd player how can i do this i did it a long time ago on another car with a line invertor i think its called but any info will help. also does my 05 crossfire have an amp already somewhere? just looking for easiest way to get a little thump with what i got