Snitch records show Nicky's car was taken out of the Pakuranga Heights impound lot on Cascade Rd at 2.30am - not long after it arrived.
It was driven around Ben Lomond Cres, reaching speeds of more than 100km/h, then returned to the impound lot before being driven further up Cascade Rd where it again reached more than 100km/h.
Nicky's car reached 113km/h in the 2.7km it travelled. Ben Lomond Cres is a 50km/h zone and the stretch of Cascades Rd that was driven that night is 60km/h.
"I was pretty pissed about it all. And I want my car back because I don't trust it being in that car yard," Nicky said.
East City Towing director Mike Holliday did not respond to Herald emails asking about Nicky's car or return calls.
When the Herald visited East City Towing's yard yesterday afternoon, Nicky's car was in the garage.
Nicky has told the police about the tow-truck company's joyride in her car.
She said it was "pretty hypocritical" that her car was taken away from her for allegedly being involved in boy-racer activities, but those who took it from her did exactly that.
Her car, which she bought five years ago, has been impounded for 28 days, but she has appealed to have it released earlier.
Nicky wonders how many other impounded cars have been taken for joyrides.
"The police officer I told this to said they'd never had a problem like this in the 12 years they had worked with them.
"And I said, 'Well, how do you know that? You only know that now because I have a Snitch. Not everyone who has their car impounded has a Snitch so they can check that sort of thing'."
A spokeswoman for the tow firm denied that the car had been taken for a joyride.
She said it was on the back of the tow truck when the truck driver noticed a figure "appear from behind our jumbo bin who then ran across our driveway towards a vehicle that was parked on the neighbouring property with its lights off. This vehicle then sped off with no lights on."
He chased the vehicle in his truck, with the Silvia still on board and the ignition on, but lost sight of it and returned to the yard.
"The truck was then driven into our yard behind two security gates and parked up with the vehicle still on the back of the truck."
She disputed the speed captured by the GPS, saying the truck could not have reached that speed.
Snitch director Jeremy Mclean said the details of the tow-truck company's joyride in Nicky's car were 100 per cent accurate. The GPS device contained a piece of hardware which recorded when the vehicle was turned on and off, where it moved and how fast it was going.
Snitch is a New Zealand company, based in Auckland.
The maximum fine for travelling up to 50km/h over the speed limit is $630.
If the speed is more than 40km/h above the limit, the driver can also have a 28-day licence suspension.
If the speed is more than 50km/h over the limit, the driver could be charged with careless, dangerous or reckless driving.