GTA 5 Indestructible vehicle

[Ond]

Hi, I've been trying to acquire an AP vehicle in GTA 5 (PC). The closest I become is with the purchasable garage taxi mission glitch (you can find it here: https://www.youtube.com/watch?v=NgnNAvBCk8A&list=PLDTpX0pxUKDqmU1s3f4z3-ex_rDhiuh0k&index=4&t=443s )

The problem is that after saving the vehicle and reloading, it loses all special abilities - let it be in a garage, or quick save. Changing to another character also destroys the car's APness. I tried to duplicate the car with the garage duplication glitch, and it did duplicate, but the 2nd car was not AP. Interestingly the first car stayed with its special abilities, so it does keep it while changing characters if that vehicle is in the garage...

So to summarize what we know so far:

-car loses its AP abilities when:

                                                  -changing characters

                                                  -saving and reloading

-car saves its special abilities when:

                                                  -kept in garage until the save is reloaded

Any idea how to save an AP vehicle? I want to do it without cheats or mods.

 

TL;DR: Want to save AP vehicle in GTA5 SP, how?