My bro in law has a '93 Ranger reg cab....for the longest, he's been running 2 sealed 8's (Memphis MClass) which get very loud in that small truck off a small Memphis amp....We picked up a pair of Assassin 10s last year but haven't had time to do any installation yet....
From what I measured, you could do 2 10s sealed but it would be very tight. In our application, I removed the center armrest and was going to fire one sub where the armrest was mounted (removing it gives a little excursion room) and one behind the passenger seat.
Basically, 2 8" subs sealed or ported, one 10" ported or 2 tiny sealed box 10s...
Jeremy