Short and Sweet way to do this.
1. Play as Franklin and ring Michael AND Trevor at the same time do not call them after pickup then try to call another.
2. Mod up your car and make it have full armor THIS WILL HELP ALOT! also go for some engine upgrades and anything that may help you but this is at your own choice.
3. Drive to the airport and head for the runways this guarantees a 3 star wanted level within moments.
4. Drive around the runways avoiding the police this should be easily done.
As you will note in the video I did this easily even with a flat tire proving how vital the armor really is for this, at least in my case.
Hope this helps some guys out!