Fire Through One-Way Glass
If you have wanted level stars, drive to a nearby haircut store in Los Santos and block the door with the car you drove in. Then, perch yourself near the window. You can easily shoot through the glass when the LSPD cannot. They will most likely stand right up to the window and sit there, but they can move around. Use this bug to raise your stars to any wished amount and you can escape or just kill cops for ammo.