Possible help upgrading sound system in 2009 Aveo 5 Hatchback M/T

[Pickles]

http://0.tqn.com/d/cars/1/0/B/R/1/ag_09aveo_trunk.jpg
See that thing folding upwards? With the strings it attaches to the rear hatch door. That piece is what you would put the 6x9s in. Also, its 6.5" in the doors