I think this may have to do with the "crumple zone" on the child's ill-advised hot rod (looks like a WRX ? = parent's asking for trouble). Looks like he hit a strong point on your Dream Edition, whilst his took the hit "head on", where a car is designed to absorb energy to save occupants. Glad to hear you are all OK.
but:
{for context: I was rear-ended by a drunk kid whilst I was stopped at a red light. His Neon had nothing in front of the firewall = completely crushed like a bier can, and I drove home. My rare Silver Arrow Edition R-129 was totaled but drivable ... auto roll bar deployed and auto-tensioner seat belts locked, enough force to tweek the Merc. so hard top would not fit / wheel scraping bent-in fender, etc... but everythng worked and drivable, and not even noticible unless you looked closely. Here's the thing:
The EMT questioned me about "you sure you don't want a ride to the ER?" to which I replied 'no thanks, I"m OK" I was holding my chest area unconsciously.... they hung around next to me ??? waiting for a pay-day I thought. But I drove home anyway because I did not want to leave my dream car to the vultures. Three hours later I woke, felt a bit sore around my belly (substantial at that time), got out of bed for a pissah, and felt the worst pain ever trying to get there (went to eleven)= spasms that were so powerful I soon blacked-out from the pain and collapsed against the bathroom door. My spouse heard this but could not open the door as I had fallen against it. When I came too I couldn't move for the pain, tried to, and blacked-out again. Next time I came to wife threatened to call ambulance, so I managed to get it together and fight the pain. At the ER it went " ALL HANDS ON DECK" and every tech = doctor in the place ran to me. OK = " 65 yo obese male w/ chest pain " apparently rings the heart attack bells. I took three IV dilaudid doses to get me to the cat scan table. Got a week of oxy (that stuff is amazing). No major damage other than all muscles/tendons/connective tissue around abdomin wrecked from g-forces / and seat-belt auto tensioner, or again, so I thought. Then sciatica hit me after the oxy script ran out. Unrelenting leg pain left me walking with a cane until I was saved by epidurals / more oxy / PT / daily stretching / exercise / pot }. It was about three years to get back to my old self. I'm now terrified of young drivers and anyone behind me. Permanantly damaged I am.
"Yeah, I'm OK" never assume this after a car crash. it could be days before symptoms show themselves.