Hiya,
I have traced the profile of the 2nd generation Prius, and overlaid it onto the 3rd generation Prius:
The profile of the nose is smoother on the new model, and the roof "peaks" farther back, and the rear is also a little different. The top of the windshield is much farther back and it curves into the roof with a larger radius.
The wheelbases are the same: 106.3", so that's how I lined them up.
[Edit: some other subtle differences:
The rear spoiler on the new car is lower down, and is tilted down a little bit, as well.
The new front fender ahead of the front wheel has a slight flare.
The trailing edge of the sides has a fairly crisp edge on the new car.]