shallow subs

I am trying to fit 2 subs under my seats because that is where the interior of my car is lacking bass the most. Under my seat is a 5'' (depth)X 11''-12'' (with) X 18" (length). i am considering this sub Pioneer TS-SW2501S4 10-Inch Step Up Shallow S4 Subwoofer (mainly because of my all pioneer...

im new here and need advice i have an 87 silverado single cab. i managed to fit 2 memphis 12" SR subs. the problem is my seat is pushed to the front and uncomfortable. and the other problem is that im a big spl guy that just want a big boom.and the memphis subs arent cutting it im getting...