Maree was due to start a hairdressing course the day after her death. At O'Sullivan's sentencing, her mother told the court she had been left with "nothing but memories" of her daughter.
She said the race was "unnecessary stupidity" and robbed her teenage daughter of "dreams [for] a 21st, a wedding, and maybe one day children".
Lawrence pleaded guilty to his role in 2013 and was jailed for more than two years, along with Jesse Ellmers, his passenger, and Matthew's brother Adam O'Sullivan, who started the race.
The three men were each given a 25 per cent discount from their sentence for their youth, previous good character, remorse and co-operation with police - something Mr Jefferson said his client deserved too.
Despite taking the matter to trial, Mr Jefferson said O'Sullivan - who had been disqualified from driving shortly before the incident - ticked all the boxes his co-defendants had and deserved the same credit.
"At the end of the day, he lost a friend and injured two of his friends and he's certainly remorseful for that."
But the Crown said the sentencing judge had "conducted a robust evaluation of the circumstances" and the jail term was not manifestly excessive.
At the Napier District Court sentencing in September, Judge Jonathan Down was scathing about O'Sullivan's lack of empathy. "Your attitude is one that is characterised as lacking insight and lacking remorse to the extent of almost blaming other people for what happened on that night," the judge said.
Justices Keane, White and Wylie reserved their decision. NZME.