The best you are gonna get for your budget will probably be FI subs. Kicker is over hyped, mass produced. Fi is decently loud, and very good sound quality. Get a decent used sq amp to run em and enjoy.
Also you should read up on frequencies, and what the music you listen to plays. I can almost guarentee you that you are going to run stock speakers with a couple subs. When you would probably be better suited with a nice deck, a good 4 channel amp, and some decent mids/tweets, or a 5 channel with an 8" sub for some beats.