1995 M-reg Ford Escort, new stereo

I have a 1995 M-reg Ford Escort. When I received the car it already had a sony head unit and 2 sony xplod 6x9s in it. I have recently acquired a 1200w sony xplod sub and a longmill puritan 2 channel amp. I am wondering if anybody has experience with these components and could give advice on the best way to set these up. I have no instruction manuals with any of the components and it does not say the power rating on the amp. Would I be best powering the speakers from the head unit and the subwoofer from the amp or could I use a tri-way setup and power all 3 from the amp? any help would be greatly appreciated, thanks.

you sould power the sub with the amp and the door speakers with the deck. sony isent a very good brand but we can work with it. if you can get the modle numbers of the speakers that would be helpful. or eny other info you have on them.Want to know some good equipment- JL,Adire Audio,Mcintosh,Brax,Helix,Eclipse,JBL,RE,Dimoand Audio,Zapco, pritty much anything DYhon,Forbidden recommend

On the12volt you give some info and you get in