He probably recommended the Q7 because it had a higher profit margin that month, or some other reason like that. I used to work in sales (electronics) and sometimes manufacturers would give us bonuses (cash + stock) if we sold a certain amount of their product in a given month. So, if we were trying to hit a Sony sales target for the shop, and someone asked should they get Sony or Panasonic, it was in our financial interest to push Sony. I wasn't callous about it, but all other things being equal, you'd push the Sony. I'm sure similar spiffs/difference in margins etc apply in car trade.
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Regarding safety: I think what they said in the 5th gear video above sounds reasonable...

I agree with what others have said: I reckon BMW cars would be above average for seating in this size+configuration vehicle, but every time I look at kids in the back of a 7 seater with their heads 10cm from the rear glass, I cringe...