GM Daewoo's official press releases says that Tosca is an acronym for "Tomorrow Standard Car". "Tosca" is also a popular opera by Giacomo Puccini. The "Chevrolet Epica" name was previously used on V200 Daewoo Magnus models sold in Canada, Latin America, China, Europe, Arabia and Micronesia. Since April 2007, the Tosca has been marketed as the Holden Epica for the Australian and New Zealand markets, replacing the Holden Vectra, sourced from Opel in Germany. It is also manufactured and sold in Uzbekistan as Chevrolet Epica since June 2007.
Daewoo's XK straight-six engines are designed by Porsche, and they are what distinguish the Tosca from other similar vehicles. The V250 is a front-wheel drive car and the engines are mounted transversely; this configuration requires the straight-six engine to be very compact and packed quite tight. The Tosca was launched with two versions of the straight-six of different displacements: the 2.5litre, which was carried over from the Magnus, and a 2.0litre, which replaces the Holden-sourced E-TEC II 2.0litre used in the previous model. Since 2006, a 1.8litre version of the E-TEC II engine model is also available in the South Korean market. This engine is coupled to either a five-speed manual or four-speed automatic transmission.
GM also announced that in early 2007 these engines will be joined by a 2.0litre RA 420 SOHC straight-four common rail turbodiesel, producing 112kilowatts (150hp) and 310newton metres (229ft·lbf) of torque. The engine, co-developed by GM Powertrain, GM Daewoo, and VM Motori, debuted in the Daewoo Winstorm, and was the first diesel engine used in a Daewoo car. In early 2008, Daewoo launched an updated version of Tosca with new six-speed automatic tramsmission in South Korea. There are two versions of six-speed automatic transmission: GM 6T40 for the 2.0 and 2.5litre pertrol engines and GM 6T45 for the 2.0litre diesel engine. At the same time, Daewoo also revised rear portion of the car, changing the rear combination lamp and rear bumper.