Sealed box? or Ported? If ported..Each 12" Targa requires 2.5cubic feet of space if ported..meaning 2x12 Targas will require about 5Cubic feet of space for their enclosure! If you have a sedan...you will have no trunk space at all. and you may not be able to fit that through the trunk opening. If you have a AUV/SUV or sedan and you don't care about the backseat..ok yun! But if sealed...I think it will fit. Kung sealed..each sub needs 1.5-2.0 cubic feet. So between 3-4cubic feet.
I know somebody selling an enclosure for 2 12" subs for only Php1,000..its vented. but is below the 5cubic feet required for the 2 targas..its more like 3-3.5 cubic feet.
Where's your location by the way? If in Manila..yeah, Visit Jeff Tan's shop, he's great for budget setups.