Project for the Tank Challenge
Since both of these two are modified from BRDM2, I built it on the chassis of my earlier 9k31. In real life BRDM2 has 4 hidden wheel to improve off road performance while Sa-9 removed them. However,these four hidden wheels will make the vehicle extremely unstable (under SP physics),so I didn‘t add them back.

NOTE:
If you want a fun anti-air vehicle and can be easily be modified for other uses(such as convey destroy), please choose 9k31(sa-9)
https://www.simpleplanes.com/a/4i9NtX/9K31-Strela-1-NATO-SA-9-Gaskin

PLEASE READ FOLLOWING INSTRUCTIONS:
1.HOW TO OPERATE THIS VEHICLE
Pitch to move forward
Roll to steer
VTOL for launcher horizontal movement and Trim for vertical movement
AG1- Set up launcher
AG2- Missile hatch
AG3- For amphibious operations
In Addition: Use normal Throttle to move in water
AG8- Lights
2.THE RIGHT WAY TO USE ANTI-TANK MISSILES:
Open missile hatch(AG2)-Set up missile launcher(AG1)-Close missile hatch(AG2)-Aim(VTOL AND Trim)-Lock target-Fire

What is 9P148(from Military Today):
The 9P148 is a Soviet anti-tank missile carrier. Unusually this anti-tank vehicle has got no proper name and is referred by its military index designation. It is based on a BRDM-2 armored scout car chassis and is fitted with Konkurs (Western designation AT-5 Spandrel) anti-tank guided missiles. It was a successor to the 9P122 anti-tank missile carrier, which was also based on the BRDM-2 chassis, but packed older and less capable Malyutka (AT-3 Sagger) missiles. The 9P148 was first seen in 1977. This missile carrier was exported to a number of Soviet allies. Despite its age the 9P148 is still used by the Russian military. It is also operational with some former Soviet republics and export operators, including Armenia, Bulgaria, Czech republic, Hungary, Moldova, Romania and Slovakia.

The 9P148 vehicle has five Konkurs missiles in ready-to-launch position on the roof and carries 10 reload missiles internally. When not in use the whole launcher with missiles is retracted inside the hull. The launcher is reloaded under complete armor protection.

A baseline 9M113 missile has a High Explosive Anti-Tank (HEAT) warhead. It has a range of up to 4 km and penetrates 600-670 mm of steel armor. Also by the time improved 9M113M missiles with tandem HEAT warheads were introduced. These can penetrate 750-800 mm of steel armor behind explosive reactive armor.

When launched the wire-guide Konkurs’ missile spins toward the target and emits a red tail light so its course can be followed visually. The operator just has to keep a crosshair on the target, while the missile is guided on the target automatically.

The Konkurs missiles were widely used on the Soviet BMP-2 infantry fighting vehicles and BMD-2 airborne combat vehicles. Alternatively these missiles can be launched from a collapsible tripod-launcher in a concealed position or behind cover. Production of Konkurs missiles reached at least tens of thousands and substantial stocks of these missiles are left.

The 9P148 is operated by a crew of 2 or 3 men. Armor of this vehicle is rather limited and provides protection only against small arms fire and small caliber artillery fragments.

Vehicle is powered by a GAZ-41 petrol engine, developing 140 horsepower. The BRDM-2 scout car has a very unusual feature. When travelling off-road four powered belly wheels can be lowered to the ground between the road wheels, thus making it a 8x8 vehicle and increasing its cross-country mobility. Vehicle is also fitted with a central tyre inflation system, which can be adjusted to suit the terrain type being crossed. It improves mobility over difficult terrain such as sand, snow and mud. This missile carrier is also fitted with a self-recovery winch. This vehicle is fully amphibious. Vehicle has a trim vane, which is erected before entering the water. On water the 9P148 is propelled by a waterjet, mounted at the rear of the hull.

The 9P148 missile launcher never proved itself in battle. There are little records and photographic evidence showing this anti-tank vehicle being used and firing its missiles in anger. Even though it was deployed during numerous conflicts since the late 1970s.