I found a quick and easy way to complete the 12 vigilante missions on Grand Theft Auto Vice City and get your armor boosted to 150.
I would advise waiting until you have access to the eastern continent before starting the vigilante missions. The eastern content becomes available after you complete the mission, “Phnom Penh ‘86”. I feel that the terrain is easier to navigate and the long stretch of highway makes it easy to get to any of the side streets.
Basically you will need to prepare a little and do some gathering before starting this mission. You will need about a rocket launcher with a least 50 rockets. If you have access to the eastern continent you can pick up the rockets by repeatedly visiting the Hooker Hotel in Vice Port near the Escobar International airport. It is located within the pool area near the rear of the hotel. These rockets will respawn after you save too.
If you have the money you can also purchase the Hyman Condo in the Downtown area. If you have collected 70 packages the rocket launcher can be gathered on the roof of the condo. You can collect the rockets from the roof of Hyman condo, go back down to save your game, save your game, and then return to the roof for more rockets. If you use this process you can collect the rockets quickly.
Now to get the process started. Begin by stealing a police car. One is usually parked outside the police station in the Downtown area which is convenient if you are starting out from the Hyman Condo.
Drive down to the pay and spray with your cop car and then start the vigilante mission by pressing R3.
Immediately use your cop car to cut off and stop any car going driving down the highway. Part your car and get into the stopped vehicle. Drive it directly into the pay and spray and leave it parked inside. This will be your instant wanted level depleting station. The parked car will remain in the pay and spray. All you have to do, when your wanted level becomes a nuisance, is get out of your cop car, parking it outside, run and get into the car parked in the pay and spray, and then immediately exit the vehicle once it is sprayed, returning to your cop car. With this method you will always have a car available to utilize the pay and spray since the pay and spray won’t touch the cop car. I advise to visit this location each time your wanted level gets to two stars.
Now we address the problem of efficiently killing the criminals. The problem is that as you damage cars the criminals can get out and hijack another vehicle or vehicles, so we will use rockets to blow up their vehicle and prevent them from escaping (One hit kills everyone in the vehicle). If you watch your map you will be able to tell what direction they are driving and be able to get far enough ahead of them without scaring them off. The whole trick is not to let them see you by getting far enough in front of their path to where you can exit your vehicle and wait for them to drive up to you.
Once you are able to strategically maneuver in front of their path at a safe distance, position your cop car off to the side and exit the vehicle, taking a stance in front of their path on the road, but not directly in front of them. Arm the rocket launcher and fire away as they approach.
You will be able to blow up the first one without a problem. The good thing is that they always travel in a parade formation with the next vehicle directly behind the first one. With luck you can time your shots to take out the other vehicles without moving from you position. If you miss one let him go and try to cut him off again by employing the same strategy of looking at your map. Don’t ram the car or get too close or they will start driving faster.
For the next set of criminals repeat the process. Occasionally remember to drive to the pay and spray to reduce your wanted level in between rounds of criminals.
The beauty with this plan is that the enemies are just like your own character. If their vehicle is on fire they can escape before it blows up. However if you blow up the vehicle while they are still inside it they will die instantly and save you the trouble to hunt each one down and put yourself in additional danger. Dispactching them with the rocket launcher will also allow you complete the process quicker, giving you extra time needed to travel to the pay and spray if you attract too much police attention.