Audio Systems: Sound System, inch subs, factory speakers

Question
I have a 1999 Grand Prix with factory speakers and aftermarket cd player.  I'm looking at 10 or 12 inch subs and an amp. What should i get for under $200 and how do i set it up?

Answer
under 200 is a little low, consider you will need money for the box and wiring too.  also most factory sound systems sound much better when the cd player is changed out.
I think if I had to buy subs and an amp for aroun $200 I'd get 2 of these subs:

http://www.onlinecarstereo.com/CarAudio/ProductDetail.aspx?ProductID=14703

and this amp:

http://cgi.ebay.com/POWER-ACOUSTIK-OV2-1200-2-CHANNEL-1200W-CAR-AUDIO-AMP_W0QQit...

that would be $200 but as I said you still will need wiring and a box.  
you you need me to reoomend something cheaper?