hey there lemon, was thinking u have disappeared along with ur new car, anyway about the optra bumper, i took delivery in the evening and it had gotten dark, i am not used to dark tints which my optra now has, it felt like every person on the road was out to scrape my car that night, anyway i was full of relief that i reached home safe, but while backing the brand new car into the compound i reversed it into my cielo because i still had not got a good idea about the rear overhang, it was just a nudge but i was shattered, i saw no damage that night, but i checked first thing in the morning and like u said not a scratch, it was like it never happened.
also i got the chance to see what lies behind the bumper before i took delivery because they exchanged the front bumper with another one as the original had a tiny scratch on it, it has a thermocole kind of material behind the plastic, maybe that takes the impact in minor collisions.