Hey guys, here is my setup for my sound system I used in my 05 crew cab. I installed it in the summer but I haven't had the chance to show you guys because of school.
After researching on here for hours, I went ahead and purchased a box on eBay even though I heard it required minor modifications. I installed 10inch shallow mount pioneers subs and used polyfill to stuff the box.
First, I had the front legs of the rear seat trimmed off (the metal part that sticks out in the shape of a L, see second picture). That increased the width of the space under the seat.
I also used 6 washers on the front legs of the seat and 2 on the rear legs to raise the seat. I was still able to tighten down the seat on all four legs.
After those two minor modifications, the box fit snug under the seat. I purchased two grill covers for the subs because they made the seat rattle if I had too much bass. The grill covers fixed that problem.
Here are the two modifications: the washers and the leg base trimmed. If you check out your the legs on your seat you will see what I am talking about.
The sub grill covers. Clamps weren't need because it was a tight fit under the seats. The covers has rubber coating on the diameter so it won't scratch the subs.
Leg space isn't compromised.
For those of you guys who are considering doing this set up, let me know if have any questions.