Referring to a number of vehicles built by Ford and tuned by Cosworth for the purposes of touring car or rally racing. Most notably among them are the Sierra and Escort Cosworth RS's, which featured the turbocharged 2.0L Cosworth YB series of engines, famed for their tunability.
These vehicles were made in somewhat limited quantities available with 5-speed manual tranismissions in RWD or AWD with a particular rear-wheel bias. Though they were sold primarily in Europe, a handful were exported to America as the Merkur XR4Ti, essentially a rebadged Sierra Cosworth RS; the Cossie Escort was never sold in the US.
That chav in his riced-up Leone thought he was hot shit, til I served him up pulling onto the M1 with my Cossie.
The Ford Sierra Sapphire RS Cosworth. A Turbocharged car exhibiting maximum levels of fun and zero levels of traction control. Often found on Southend Seafront going "baaaaaaa-tshh" over and over again. Also Escort Cossie, 3-Door Cossie, and the rare and pony Gartrac Escort Cossie.