The 2008 Kia Sportage has adequate room, reinforced by higher-quality construction than you might expect for the price.
Cars.com reports that "the Kia Sportage seats up to five." Kelley Blue Book notes that "Kia Sportage seating position is appropriately upright and, while the standard sunroof encroaches slightly on rear-seat headroom, most adults will find either front or rear seating to be generous," adding that "the fifth passenger's area, in the center of the rear seat, is somewhat marginal." Overall, however, "legroom is adequate, and headroom is generous...both the leather and the cloth seats are comfortable, with good side-bolster support," according to ConsumerGuide.
Cars.com reports that "with the 'Drop and Fold' rear seating system, the seat cushion lowers and the backrest folds flat, yielding 66.6 cubic feet of cargo space." ConsumerGuide notes that "groceries fit fine behind the rear seats, but there's little room for large objects," and "the Kia Sportage rear seats fold easily in one motion to form a flat load floor."
Materials are above average for the price and class. ConsumerGuide reports "dashboard control dials have rubber grips, literally a nice touch," going on to note "for interior materials, [Kia] Sportage is a cut above Honda CR-V and is slightly upscale of Tucson." Kelley Blue Book praises the "quality plastics, with an almost quantum improvement in both appearance and texture."
Cars.com reports "other than a little tire noise on some surfaces, the Sportage is quiet, though the engine gets snarly at high rpm." ConsumerGuide agrees that the "4-cylinder engine is coarse and buzzy...the V6 is quiet at cruise, but it strains loudly at higher rpm."