Back in the 1980's the 9th Infantry Division (Motorized) up at Ft. Lewis was the Army's Testbed Organization. They got all kinds of fun gizmos and toys to play with. (I went there for ROTC Advance Camp. Great fun.) Anywho, that there is a Fast Attack Vehicle. M60 Machine gun mounted on the main body for the assistant driver and a Mk19 Grenade Launcher up top for the gunner. IIRC, some even had TOW missiles mounted on them, since 9ID was somewhat light in the Armor department (I believe they did have one, maybe two Armor battalions in 9ID, as opposed to zero in the truly "light" divisions and five or six in the Mechanized or Armor Divisions.)
Yes, they were fun as hell to drive.