Armed with a smooth and powerful V6 engine, as well as improved braking, this version of the Sienna was our top-rated minivan of its time. Because it was also the only one available with all-wheel drive, we tested both front- and AWD models. Our readers reported the AWD's run-flat tires wore quickly and were expensive to replace. A slightly stiffer ride and a loss of one mpg overall are other sacrifices for AWD. Stability control is standard.