The Warthog and You
The Warthog is a vehicle designed around teamwork; the more people are in it, the better it functions. It can accommodate up to three people: a driver, a gunner and a passenger.
The Warthog combines mass with agility and is able to mow down nearly any creature in its path. Even light vehicles like the UNSC Mongoose and the Covenant Ghost can be destroyed if a Warthog rams them with enough velocity. The driver's role revolves around mastering the vehicle's role as a means of transport and as a weapon. While deadly up close, the open-topped vehicle is vulnerable to boarding and grenades if it slows down or gets stuck near enemy infantry. Conversely, if it remains too far away, the rear-mounted gun turret will not be able to concentrate its fire to eliminate foes before they can unload long-range anti-vehicular weaponry. A good warthog driver will weave in and out of cover, give the gunner a prime angle on enemies and give quick rides to passengers during objective games.
The Warthog's gunner position is so enviable that some people will resort to physical violence in order to secure it. Consisting of a machine gun turret with unlimited ammo strapped to a rotating mount, the gun can unload a steady stream of high-calibre bullets that are most effective between short and medium-to-long ranges. More precise than the standard assault rifle but not able to match a scoped gun's range, this makes it ideal in most combat situations where the Warthog itself is vulnerable to attack. This means that the gunner's position, while attractive, is only as safe as the Warthog's driver. Any target too close to the vehicle can duck under the gun's lowest angle and have a field day with the occupants. Additionally, an immobile Warthog is as good as dead: unlike a machine gun turret, the Warthog's gun is made more vulnerable by the vehicle's large size where any grenade or explosive can land a killing blow. By knowing those risks and preparing for them, a good driver matched with a good gunner can become a formidable force on the battlefield.
The right seat of a Warthog lacks weapon or protection. A passenger riding shotgun will tend to brace his legs against the dashboard and side panel in order to maintain stability and have an elevated position from which he can cover the front 180 degrees with his weapon. Since few handheld weapons are as powerful as the Warthog's gun, the passenger tends to be little else than a meat shield for the other two occupants in most combat situations. In objective-based matches, however, the Warthog's speed and power tends to make it a good ferry to get a single teammate in or out of a hotly contested area, especially as, for example, a flag carrier in Capture The Flag mode cannot drive a vehicle or become a gunner, but can ride in the passenger seat. The passenger can also act as insurance when an opponent gets too close to a pinned Warthog for comfort, able to dismount and intercept without requiring the driver to leave the vehicle or the gunner to leave his post.
You Against the Warthog
The Warthog is powerful, but not invincible. For obvious reasons, anti-vehicular weapons tend to be especially effective against it; the only way for a Warthog to survive missiles and rockets is to dodge them outright. A single, well-placed sticky grenade will heavily damage it, sometimes even destroy it; a regular fragmentation grenade will make it flip easily. Finally, given that the vehicle's occupants are not fully protected by doors and windows, they can be sniped or shot out of it even while in motion (often with hilarious results).
An agile Warthog is a dangerous Warthog; robbing it of its momentum through explosives or driver-defenestration will often spell doom for those inside.
The Warthog will be available as a special unlock in Forza Motorsport 4, unfortunately you can't drive it.