While I will agree that JL makes good subs and their amps are tanks I would recommend a few other brands before JL, especially for free air applications. For the subs I would recommend Image Dynamics or Elemental Designs. I am putting two 8" Elemental Designs subs in brothers LS. I have one 10" Image Dynamics in my girlfriends Mazda 6 in a free air application and it hits hard! I would recommend Alpine Type R subs over the JL also. I had 3 12" with a Pioneer Premier amp and it hit 145.8 DB at competition. As far as amps I would recommend Alpine, JL, PPI, MTX, DEI, and Viper-currently have one(they were part of the DEI line then were discontinued so you can get a really powerful amp for cheap if you can find one). Other than that just listen to as many subs as you can and pick what you like best!
Have fun with it.