My '06 STS was rear-ended by an uninsured cell phone using idiot when it was barely a week old. Like you write, apparently only cosmetic damage to rear of my STS and complete destruction of the Celica's front end. But beware...
What you see at the back of your car is the bumper COVER. The bumper itself is a beam mounted on energy-dissipating struts that is hidden by the cover. Have those items evaluated and replaced if necessary. Also have your trunk floor checked--mine buckled slightly and had to be pulled. Check your exhaust pipes if the chrome tips were hit. My car got a cat-back replacement because the passenger-side pipe was kinked. Finally, replace your rear parking assist "buttons".
What you see at the back of your car is the bumper COVER. The bumper itself is a beam mounted on energy-dissipating struts that is hidden by the cover. Have those items evaluated and replaced if necessary. Also have your trunk floor checked--mine buckled slightly and had to be pulled. Check your exhaust pipes if the chrome tips were hit. My car got a cat-back replacement because the passenger-side pipe was kinked. Finally, replace your rear parking assist "buttons".