Mr MacKenzie died at the scene.
Shang's residence, to which he was bailed, was only a few streets away from the McKenzies' place.
Mr MacKenzie's father Martin spoke of his horror at finding out as he walked his dog past the property.
He and his wife Tania started to recognise the Shang family's vehicles and their grief was sharpened with each encounter.
And another chance meeting brought even more pain to Mr MacKenzie senior.
He walked past a local cafe one day and spotted Shang outside.
It was too much to take.
"I went up to him and said: 'Do you know who I am? I'm the father of Luke MacKenzie who you killed'," he said.
"Internally I wanted to punch his lights out ... he was visibly shaking when I was talking to him but I walked away very shortly after."
Shang will be deported to China after serving his sentence, something the victim's family said was a relief.
But it was also the "little things" that had brought them great pain in the two years since Luke's death.
"Last year we had to go to about eight weddings of people of a similar age and the first couple were just unbearable," Ms MacKenzie said.
"We don't tend to go to funerals now. It's too hard."
Things like shutting down their son's bank accounts became an "unbearable trauma" and a run in with a finance company did nothing to sooth the hurt.
After constantly receiving promotional material in the post, Mr MacKenzie called the company to explain the situation.
But instead of apologising, they told him a copy of Luke's death certificate would have to be provided before the correspondence ceased.
Outside court yesterday, a tearful Mr MacKenzie said the sentencing changed nothing.
"Our love for Luke is the same now as it ever has been," he said.
"You have two choices: it either destroys your life or it strengthens you as a family. We chose the latter."
More than 1000 people showed up to Luke MacKenzie's funeral; evidence, his friend Jason Adriaase said, of "what a unique and caring person he was".
"Luke was the glue that held our group together."
To add to the tragedy, the 23-year-old died on his mother's 49th birthday; an anniversary that would now forever be a sad occasion.
And the family's mourning was not just for their lost son.
"Not only did we lose a son, we lost a daughter and eventual grandchildren," Mr MacKenzie senior said, making reference to long-term girlfriend Ashley Sheppard.
The family could have called on the court to jail Shang for the maximum term in the circumstances -- five years.
But they refused to be eaten up by their hatred and gave their blessing for a sentence of home detention.
Now they intended to focus on the son they loved and lost.
"We honour Luke every day and we made a conscious decision right from the beginning to talk about him and have photos of him around the house, enjoying the person that he is and was."
