Didn't think it was even possible to keep a police car for yourself, did you? If you did want to get one of these for yourself, and maybe play police cop, follow this handy guide.
Assuming you have said car of choice, bring it to the garage. The key to this trick is how you stop the car to bring it in.
OK, so you should park the car at just the right distance that when you get out of the car, the garage door won’t open, but your character will automatically go in. If you haven’t figured out how to do this yet, go to the garage and practice with cars you already own until you have mastered parking at the perfect distance.
Now, pull out any of your arms (apparently a carbine rifle works best), aim away from the car and the garage, and start walking backwards, towards the garage. Aim at where the driver door is as soon as you can, and hold Y.
If you did it right, you will see the cutscene which shows you driving into the garage at the same time that you actually get in the garage.
That’s it! If you need more help, you can look at the visual guide below.
Source: Reddit
