Tank stealing tips:
1. Arm yourself for a big battle w/ the VCPD. Buy at least 16 rockets (make sure you've done Phil Cassidy's missions first), 40 sniper rounds (more is better

), at least 2-3 clips of Colt Python ammo, MP5 helps too along w/ fast reload (from scoring a 45 or higher on Rifle Range). Grenades and other weapons are optional.
2. Go to the Skumhole Shack and save your game if you've bought it. If not save somewhere close by.
3. Jack a car and drive to the Skumhole Shack. Go up the stairs and turn around so you are facing the street.
4. Do whatever you want, snipe bypassers, shoot them, blow up cars, whatever it takes to get the cops attention.
5. Once the 3rd star is flashing, you should see and hear Undercover Cheetahs pull up. Switch to your MP5 and shoot the crap out of them, along with any VCPD officers. This should bring you to 4 stars.
6. Listen for the copters; when you hear them, switch to your rocket launcher and shoot the copter down.
7. Once the 5th star flashes, suicidal FBI agents should pull up w/ MP5's and attempt to gun you down. Shoot their cars w/ rockets and continue to scan for copters.
8. When the 6th star flashes, here comes the Army. Listen for explosions, a tank can't be too far down the road. Once they pull up, run down the stairs to lure them out.
9. Then quickly run back up the stairs and snipe them from behind the railing.
10. Jump down from the shack and get in the tank. Be careful not to get busted as the tank is slow.
11. Don't shoot anything. Just get back to where you can save, preferally your Hyman Condo if you've bought it.
12. Park the tank in your garage and get out.
13. Save your game and reload to get rid of the wanted level.
14. You now have a tank.

Have fun!
