Get a helicopter with a grapple. Deploy the grapple and look for a vehicle. Take that vehicle (for example, the Raven from Universal Petroleum) and use the grapple to grab it. Next, take the vehicle to a body of water. Lower your helicopter until the vehicle is in the water and you are hovering. Wait a few seconds until you hear the explosion. Then, fly up and take your vehicle to dry land. Release it from the grapple. The vehicle will be in perfect condition (or the condition in which it was grabbed). You can get out and shoot it without the vehicle exploding, but you will not be able to drive it.