the monomille/bialbero is like the original on the 600 floorplate but alternatief can also a 850 or even a simca 1000 to make a abarth simca the 1300 OT fits on a 850 coupe ,but again also possible but not yet fitted a berline or simca 1000 must go the biposto and 2000 spider have a tube chassis and x1/9 prototypo fit on x1/9