This is a brand new method to duplicate cars really easily in GTA online and i thought I would make a text tutorial to help people out with it!

Steps:
1. Have a facility and a regular garage (Most people already have).
2. Fill your facility with free cars (Elegy) to save money when replacing.
3. Drive a car into your full facility so you have the facility full screen up.
4. Then have a buddy drive into you and push your car away from your facility.
5. When you are a decent distance away (Doesn't have to be too far) accept the screen and then exit your car.
6. Kill yourself by choosing the easy way out.
7. Take your friends car you want to dupe and drive it into your facility and it will ask you to replace a car, replace any car and then you have duped the car.
8. Get in the car and drive out of the facility. It should kick you out of that car. - Very important!!
9.Leave game and join back.

This is a really easy method too do and it takes under a minute to actually perform from personally doing it. Good luck everyone.