MEGAS XLR stands for Mechanized Earth Guard Attack System eXtra Large Robot.
This robot is very powerful and has many weapons. It uses a muscle car as main cockpit, specifically an unlicensed approximation of a Plymouth Barracuda, as they were unable to license the real car.
The steering wheel of the car is actually used to control Megas, just like the Boss Borot robot from the old Mazinger Z Japanese anime series (probably as a tribute).