I have just purchased a 2005 FX4 Supercrew and would like to install a couple of subs behinde the rear seat. The problem is that the rear seats don't move forward and I don't know how much room is back there.
Has anyone done an install like this or have any tips?
If there is room is there a enclosure that is made to fit behind the seat?
I have seen the box that fits under the rear seat "is this the only way"?

 

I assume you're referring to an F150. There's zero space behind the rear seat. Notice how the seatbelts are attached to the seatback, rather than to the C-pillars as they were in the older 150 Screws... to get the structural stability to deal with those belts, the back has to be bolted to the rear wall.

This is also an issue for those of us using the 150 Screw as an emergency response vehicle, and a royal pain in the rear.

 

Yes I am talking about the F150. So, I guess there is no way to mount anything back there except maybe a amp of two. Haven't looked back there yet but, i guess that is my next step.

 

The rear seat is shoved up against the back wall. You *might* be able to get an amp back there if there are voids in the seat back (likely), but you're going to have zero airflow. I wouldn't recommend it, unless you like the smell of burning electronic components...

 

Maybe you could try doing what I did with my '03 supercrew. I first used a cardboard template to see what would fit, then designed a speaker box to fit under the rear seat. I don't know if the seat arrangment is the same on an 05, but it's worth investigating. Let me know if you need any additional information.
TonyC

http://www.geocities.com/tony_cricco/techie.html