[SubaSteevo]

I've tried a couple of different setups in my car, every aftermarket reciever I tried will interfere with the door if you place it in the bottom space. The pocket I have with the flip-up door will interfere if on the bottom as well. To get around this, I flipped the pocket upside down. Both headunits I've had installed fit without interfering with this setup (headunit on top, pocket flipped on the bottom). The headunit I just put in my car is a Clarion with a volume knob rather than buttons like I had on the Pioneer. I was worried the knob would hit the cover, but it fits just fine.

If worse came to worse, you could drill new holes in the cage to allow you to push the headunit back farther, but then you might run into clearance issues with the wires in the back.