Testarossa - 512 TR - F512 M
The main differences between the 512 TR and the F512 M are related to the exterior, with open headlights, a redesigned front bumper, round lights at the rear and a new design of the wheels. Internally there were some small visual changes, like the steering wheel design, alloy knob on the gear lever, adjustable aluminium foot pedals, a more refined air conditioning system, trim details and optional sports seats. Mechanically there were further improvements to the engine, the suspension and the braking system.
The drawings shown below show some designs that didn't make it ...
[Source: Ferrari F512 M by Bruno Alfieri / Automobilia #32]