speakers

I am going to put 2 12" subs with a 1000 watt amp in my 2002 ls with the alpine 6 disk indash changer how might i go about doing this.As in were is the existing sub if one and the stock amp. and do i need to take these out or can i leave them in.

Factory sub is mounted to the underside of the package shelf. Amp, enclosure, and drivers are all in the same molded package.

I would remove it.