At the Paris Salon in October of 1994, Ferrari introduced the final version of the fabulous Testarossa series - designated the F512M. The letter “M” stood for modificata, with the vehicle featuring a modified design, a modified engine/transmission and various other internal and external modifications that truly made this rendition the “beast” of the Testarossa series.
When Ferrari decided it was time to replace the Berlinetta Boxer, they started with the assumption that power would be from a 180 degree V-12 engine and that the car would be defined by exceptional style and design. So the Testarossa was born: a collaboration between Ferrari and design studio Pininfarina. And although the original Testarossa displayed ground-breaking styling, design and performance, Ferrari did not rest on their laurels. There was constant improvement and enhancement of 1984’s Testarossa and it eventually evolved into the 512TR of 1991 and finally the F512M of 1995. With each evolution the styling, interior and performance were improved in a car that was consistently capable of top speeds in excess of 180 MPH, 0 to 60 MPH times of less than 5 seconds, and attaining 0.9G of lateral acceleration.
http://www.f512m-usa.net/info.html