how_much_to_cut

why do you need to cut that?
to fit subs

Yep. I cut out the middle so I could carpet and reuse the outer part. Makes it more finished...

Wow! how hard was that to do? it pits my install to shame.

It wasn't hard at all. Took me and my dremel about 20 minutes to cut out, then about another 30 minutes to carpet it.

How do you keep it secured to the back wall

Most of the clips that secure the storage bins to the back wall are left on that trim that I used. Snaps right in to place!

Thanks il try that mod this weekend with my set up

Did you have to take your back seat out in order to remove that piece?

No. But, you gotta use a little force to pop the pieces loose that are kindof glued to the wall.