The car was designed by Centro Stile Alfa Romeo, under the control of Walter de Silva, and was facelifted in September 2003.

In order to keep the design fresh, Alfa Romeo made a series of modifications to the Lancia Kappa based underpinnings, radically changing the suspension set up, and also taking a clean paper approach to the interior.

The 2.0-litre V6 Turbo model was dropped because of marketing problems, the 2.5-litre V6 underwent a revision and now had a power output of 188 PS (138 kW; 185 hp).

[citation needed] In October 2005, the Alfa Romeo 166 was officially withdrawn from sale in markets for RHD.

Sales of the 166 never grew as Alfa Romeo had hoped, following the facelift in September 2003, and the additional lack of a diesel engine in the United Kingdom, Australian, and Irish markets limited its reach into company car sectors.