i put this info up on another post but seeing as alot of people are having trouble with this thought i put up my own post hope this works aswell for you guys as it has me

1.use weasel apartments seems to be the best at not despawing cars between the garages there is a tree back the car you want to store right up against the tree so the boot is touching it and car is pointing straight as in not blocking garage then exit the car and tap a and move in direction your leaving car this should leave the door open and you in front of your garage now just walk in

2.you should see your car still outside as you walk in set spawn location to garage an get into car you want to switch it with

3.once in side the car sat down and door closed bring up phone and go left to quick job press a on random

4.now at the confirm screen press a and right trigger together at same time if hear garage door open you got it right at this point i let go of a but keep holding the trigger until mission joining screen appears release trigger wait until quit appears and back out you should appear in glitch garage

5.turn around and run like hell to your car (as you only get a few seconds witch is why the leaving door open is important)get in and you should glitch in and drive out the garage just reverse into garage and cars yours

it might fail once or twice but by far best way i have found it can be done solo as i have done this with all my cars i stored but having a friend will help as if it does fail and you appear at the random job location the car will be gone and have to be brought back in although the going to gamestore and waiting for 2 flashes before signing out part of bringing in car can be done at this point but having friend would stop this and this is the only way doing this method i know of that will despawn the car but after trying so many other ways and failing ALOT i only failed with this a few times like 2 or 3 times before had success