Not sure if this has been posted yet but here it is.

To do this glitch you need someone with the limited edition cars and be in there garage in the car of your choice. Ex. Hot knife.
Once youre in the car the owner of the car goes to the dynasty 8 website and buys a appartment that their apartment is already in.
Once he buys the apartment it will put you and your friend outside with the car.
It is now yours to keep, the only downside to this glitch is that it doesn't actually appear in your garage, you have to call the mechanic to bring it to you every time.