Do the "Shake Down A City Council" job in the Boss tier in New York. You will randomly loot the armored limousine.
do the job Storm The Presidential Palace
To get a car bomb on Mafia Wars you have to buy it using reward points.
You can get the Armored State Car by completing the "Storm The Presidential Palace" job which is a job in Cuba.
Cuba (El Padrino) - Storm the presidential place
the town car is located in the mafia store under the vehicle category.
But their no longer available
you can get it by doing black mail a car dealer job.
Used to build Thai XS Max
You can find one when you open a Gold Chest
You have to talk to the dude on the corner of the garage place for the kit.
If it is in the new Las Vegas city ,try the job "Blackmail a car dealer".