subs in 1st gen double cab

I have been doing a lot of searching and it seems the only options are to put 2 8s behind the seat, sit a box in the floor or marv made the suggestion of a custom box to go in the center of the floor and up onto the seat so it could be used as an armrest too. My question is what kind of sound quality are you getting out of 2 shallow mount pioneer subs?

2. If I go with a double din cd player instead of a regular do you have to buy any trim or accesories or will it mount without any?
Its an 03 double cab.