At about 183 inches long and 74 inches wide, with a wheelbase of 110.6 inches, the X3 is sized almost identically with the Audi Q5, and a bit longer than the Mercedes-Benz GLK Class or shorter than the Cadillac SRX.
The 2013 X3 makes good use of its space, with firm, properly angled front seats surrounded by copious head and leg room. Second-row passengers have even more space--it's where the added length is most noticeable, and where the X3 takes the lead over vehicles like the Q5 and GLK Class. The back seats have room carved out for feet, under the front seat, and head room soars. Get the sport seats in front--which we recommend--and you get extendable thigh bolsters and more aggressive side bolsters; they feel a little firmer at first, but they're great for long-distance comfort.
With seating for five, the X3 has a large 19-cubic-foot rear storage area that swells to 56.6 cubic feet when the rear seats are folded down. The rear seats split 60:40, or optionally, in 40:20:40 segments for better flexibility. The cargo area itself is lovingly detailed, with rich carpet, some of the most refined seatback latches we've ever seen, and metal cargo rails with zero tolerance for poor fit.
Overall, the new X3 is so much more sophisticated in design and execution, especially inside. All the materials from the middle of the doors on up are soft-touch, with really nice-looking grains, and the net effect is that the cabin has a muted ambiance that helps soak up harsh sounds both from conversations inside the car and, we suspect from the outside. Although the ride is firm, and you do hear the mechanical sounds of the four-cylinder engine a bit at idle, the cabin is in general very well isolated from road and wind noise.