I installed Focals front and rear, Rockford Fosgate Prime amp, Kicker 10" comp sub box in trunk and Kenwood KDCX997 head unit, all low key and easy to install. I liked the Kenwood head unit because it is all black and variable LED display so you can pick your color.
I installed the sub box because it gives more bass and is removable. I have it tied down with L brackets.
The system is awesome.
Here's a couple of pictures.
