Help with my audio setup in my 97 taurus?

im lookin to upgrade my audio system in my 97 taurus with a Dual XOBP12D 1100W 12" Illuminated Bandp Subwoofer System, and my uncle will be buying me an amp for it too. any thoughts on what type of amp would be great because i dont kno much about car stereo, and how would i replace the head unit on my taurus because of the round dash..iv seen pictures of taurus' with aftermarket, normal rectangular head units but im wondering if itll cost much extra with it being round..thanks!