Following the failure of the M114, a new reconnaissance vehicle was needed. One of the answers was the XM800 Armored Reconnaissance Scout Vehicle (ARSV), for which two contracts were awarded: One to FMC for a tracked vehicle, the XM800T, and one to Lockheed for a wheeled vehicle, the XM800W. Unfortunately, both of these vehicles ended up being cancelled and superseded by the Bradley. This suggestion will focus on the XM800W.
The XM800W was a wheeled 6x6 vehicle. It had a unique articulated hull, with the front section including the two front wheels able to twist to give it extreme flexibility for rough terrain. It weighed 7,700 kg (8.49 tons) and was powered by the General Motors 6V53T Diesel Engine, the same engine as in the M551 Sheridan. Unlike the XM800T, its engine power was not reduced for reliability and it had the full 300 hp, giving it a power-to-weight ratio of about 35.34 hp/ton. It was also fully amphibious, with a swimming speed of about 5 mph (8.05 km/h) using an aero-jet water-jet propulsion system. Initially, it was to use the same turret at the XM800T, but it eventually ended up with its own turret seen in the above photos. There seems to be another early turret design available for it as well with a flatter turret:
The armor on the vehicle was light, with the hull being made of aluminum and the turret of cast aluminum and steel. It had a roof mounted 7.62mm M60 machine gun with a gun shield for the machine gun that could be flipped up. It was fully turreted with a stabilizer and laser rangefinder. The XM800W is armed with a 20mm M139 autocannon for a main gun. This is a US-built version of the Hispano-Suiza HS.820/Oerlikon KAD, the same gun as found on the R3 T20 FA-HS. The gun had access to APDS rounds, the same as are available for the Wiesel 1A4. It was operated by a crew of 3.
In War Thunder, I see the XM800W as being a good higher ranked autocannon-armed wheeled vehicle. Its performance seems mostly similar to the Wiesel 1A4, with a larger size but also more mobility and a full turret with a stabilizer. Its gun features the same ammunition as the Wiesel 1A4 including the APDS, but is faster firing as it’s a version of the Oerlikon KAD, seen on the R3 T20 FA-HS. It would be excellent to see both XM800s, both would provide fun American counterparts to the Wiesel 1A4 and Type 87 RCV (P). Additionally, the American tree is currently lacking in wheeled vehicles, which is something the XM800W could provide around Tier V.
Thank you for reading my suggestion.
XM800 Armored Reconnaissance Scout Vehicle - Wikipedia
Lockheed XM800W (ARSV)
Lockheed XM800W (ARSV): Photos, History, Specification
Lockheed XM-806 (XM-800W): armored combat reconnaissance vehicle - pikabu.monster
My old suggestion for the vehicle has a list of additional sources as well that had more information, but unfortunately several of the links don’t work anymore: