Where is the third generation forum?
Everyone talks as if there are only two versions of the Scion Xb.
Well, the first Xb made it clear Xb stood for extra boxy.
The second version has only brake lights, tail lights, and turn signals in the two rear clusters, with a single large reverse light on the left side of the bumper. It also has a very angular front, at each side, where the black plastic fillers are; where many folks add daytime running lights or LEDs.
The third version (the one I own) has done away with the single reverse light in favor of the rear light clusters on both sides having the signals, brake and running, and reverse lights. The front end where the plain black panel are is almost perpendicular to the ground.
All three vehicles are different.
I know this this when I parked next to a second generation and did a side by side comparison. There may be more differences, but those are the ones which were obvious.