Does changing cars while having wanted stars, make it harder for the police to find you?

Solution 1:

Yes, changing cars does make it harder for the police to detect you.

If your arrow icon on the minimap turns grey, the police doesn't know that you've changed your vehicle and thus will need to get very close until they can identify you. They still can detect you if they get close enough, so having a grey icon doesn't mean you're safe; only that your chances of escaping have greatly improved.

To do this you have to change your vehicle while the police is looking for you, i.e. not chasing you. If you steal your car, chances are high that the police will still know where to look; granted, I never thought about killing the previous owner, but my guess is that if someone witnesses the carjacking, you'll have to kill them as well.

The easiest way to pull off such an escape would be to drive into a parking lot, then steal an unmanned car when the police has lost sight of you. If the alarm goes off, you'll want to avoid the police altogether, at least until the alarm ends.