You will have no wanted level and no cops will chase you.
You can explore the entire map freely without taking risk.
Drive one of them until the garage door opens, and then drive it half way in and get out of the car. Next, get into the other car and drive that all the way into the garage. Also if you visit places very far away than no gang war will be provoked.
Then get into the car half way in and drive it the rest of the way in and get out and leave the garage.
In games like Morrowind and Oblivion, they solve this by warning you've killed someone important or just making them invincible.