During the early 1950s, Abarth's business was booming in three main areas ? custom-built racing cars, tuning/accessories, and modification of production cars. Abarth worked on modifications with a number of manufacturers in Italy and elswehere, and it was for the company's collaboration with Fiat that it became best known. Abarth ?s version of Fiat ?s little 600 appeared in 1956, followed by the 500s - the company would continue to produce sporting versions of most of the major Fiat models, bearing the distinctive scorpion and shield logo, until 1971, when Abarth became an integral part of the growing Fiat empire.