how many of what size subs?

Its an 83 Suburban. LOOooooots of room. I listen to all types depending on mood.  country, rock, r&b..

I understand the bigger the more exp.. but comparing 2 10s to the price of 112..and the 2 10s are more exp.

The difference in size is really how load it can get, the bigger the sub of that sub's line the more watts it can take. A suburban you can fit dam near anyone ya like. I find though if ya use say two 10's instead of one 12 its a stiffer base. But this all depends on many factors. My advice see if you can listen to any of the sub your thinking about in action, ignore peoples advice on brands unless there is a reliability problem because they might not like what you like in a sub.

first things first.... what is your budget?

your talkin' bout speakers next to the rear seat and in the center counsle... your getting into trick stuff if you want it to sound good.

what kinda amps are you running... or plan to run?

do you want sound good bass or SPL bass?

alot of things unanswered, so lets start with budget! cuz like its been said, you got unlimited space for a killer system, though those older 'burbens rattle like crazy... fit some 'mat into your budget