Sub Size and Boxes

[xChEwYx]

I drive a 2002 GMC Sierra 1500 ext cab and i am going to be taking out my back seat or maybe even running a sit through to house either 4 12s or 15s basically I'm working with 4.8ft w x 3.75 ft h x 2 ft l if i remove the back seat... but what I'm really asking here is two things.. 1) if i wanted could i be able to fit the 4 15s in a ported box back there and have it sound good or would i have to do 4 12s? 2) If i were do to a cut through i just want to know some pros and cons of this if there are really any.. so can you leave either some recommendations on what to do here

Im thinking of going with some Rockford Fosgate T2s or some DC Audio subs if that matters