Step 1) Get to Chiliad State Wilderness by Rocky Road Parachuting
Step 2) At 19:00 go over the mountain like I do in the video and you will see 2 police cars and a helicopter, infront of those to the left of your vision the Marachi car will be there
Step 3) Snipe the driver of the car otherwise they will drive off the edge of the cliff and blow up
Note: It must be 19:00 in your game otherwise it will not spawn. Also if you don't see it do a 360 with the camera view.