This Trophy is a mission based trophy about halfway through the single player campaign, and will be unlocked upon completion of the mission Blitz Play.
Open below for the spoiler version of this solution.
*** Spoiler - click to reveal ***
This mission is technically the forth they have to do for Dave and the FIB. Start-able after "By The Book"
To complete it you have to collect some stuff for the heist (this can be done in any order and is 4 more missions):
1. A getaway car - any 4 door car that has to be parked somewhere private (don't worry where you put it, they tell you if it is a bad spot/car, and they GPS to it after the heist - I used an SUV, and the best place I found was under a bridge in the concrete sewer - which is near the site of the heist so it makes for hiding from the police easy also (2 birds 1 stone)). Oddly enough, I don't remember this being a mission, only a phone call.
2. A Trash Truck - it's a mission called "Trash Truck". Just go to the icon (the truck is driving around), wait for it to stop to pick up trash (or stop in front of it) and then hijack and drive off to the drop off spot in the FIB lot. You may have to loose cops (Don't scratch the truck, reach the top speed, and do it all in 5 minutes to 100%).
3. Boiler Suits - it's a mission called "Boiler Suits". Just go to an Ammu-Nation, walk up to the clothing rack on the right and by 3 boiler suits and exit (do it quick - in 30 seconds - and buy 3 different colors to 100%).
3. Masks - it's a mission called "Masks" (there is a pattern here I think). Go to the Mask Store on Vespucci Beach (should be an icon), pick out three masks, and walk away (do it quick - in 20 seconds - and buy 3 white hockey masks to 100%).
4. Tow Truck - it's a mission called (you guessed it) "Tow Truck". Just go to the icon for the Tow Truck, steal the tow truck, and drop it off in the FIB lot (Don't scratch the truck, reach the top speed, and do it all in 3 minutes to 100%).
Once the above is collected, Blitz Play can be started by going to the FIB lot. You'll put on your outfits and masks, and start out as Michael driving the Trash Truck. Drive to the spot and turn the truck sideways blocking both lanes of traffic. You'll then switch to Franklin and drive the Tow Truck into the side of the Armor Truck after it stops. Get out, throw a sticky bomb on the door, and detonate it. The cops will then show up, take cover and kill some (feel free to switch back and forth from Franklin to Michael). After a while, you will be prompted to switch to Trevor for sniping to take out the 3 snipers on rooftops. After taking out the snipers, a chopper will come in. Shoot it down with Trevor (one well placed shot to the pilot works wonders), and then take out the rest of the cops (probably will need to switch through everyone to get them all. Franklin will then have to take the garbage truck to wherever you parked your getaway car (may have to loose some cops). You will then have to blow up the garbage truck (make sure not to do this right next to your getaway car as you can blow them both up) by any means necessary. Then drive away and you'll switch to Michael. Follow the directions to drive to Devin's house and you'll have a chat with him. After that chat, the mission will be passed and the trophy will be awarded.
To 100% Blitz Play, make sure that you shoot down the helicopter as Trevor, kill 12 cops with headshots (lock on and press up slightly), finish with an accuracy of at least 60% (see head shots), and switch characters 10 times.
Also, just want to note that you don't have to 100% any of the missions to get the trophy, only passing the missions is needed.