I have to say Rockford fosgate makes the best sound but they would be more money than you got to spend ... So I would try to stick with kicker or kenwood and if you can find them in your price range Polk makes great all range speakers
But +1 on the 460 sound system if you have that just add a woofer
In my gt I left the 460 and simply custom built a box for 2 rockford fosgate p3 12s and a 1500watt singe channel amp but that gets so loud you can feel your heart change it's beat
However you could risk ebaying the amp and subs (new in box) but not from an authorized fosgate dealer you won't get fosgates warranty but you could get my setup for about 800$ fosgate stuff almost never breaks so with a little luck...
Happy times ahead