"Jimmy! Just the man! Listen - I need a Shubert Armored Van. Couple of friends of mine have a big heist planned and they need a bulletproof getaway vehicle. There's a security firm that does a daily run through the city, your only chance will be when the driver stops near the bank. You in?"
It can be difficult to avoid police involvement on this one, however it doesn't really matter. Even if the police are chasing you when you arrive at the garage you can still end the mission. Plus, it's nearly impossible to damage an armored truck so you should receive the full payment even if they've been shooting and ramming into you the whole way.
From the start head around the corner where the armored van will be in the parking lot of the bank along with five armed guards. Kill the guards outside the van and then pull the driver out and kill him as well. The instant you enter the vehicle you will get a three star wanted level on the license plates even if no police are around. Drive it to the garage in West Side where you will receive only $1500.00 for your trouble.