Need help with EQ and Summing devices
 

hey guys i just got a system put in my 09 fx35, and i kept my original navi unit , so output to my system isnt very good, and i was told i would need a JL summing device and a JL cleansweep installed to help make my system sound better. My question is do i need both of these things? and if so do i have to use a summin device with the Cleansweep or can i go a different route?