spearsoftwilight

HELP - I'm a pensioner living in Leicestershire with no real knowledge of motors. I have a fairly rare 2008 POLO 1.6 SPORT (FSi). The rectangular back exhaust box is beginning to age and will need replacing soon enough but the prices I am being quoted are prohibitive (are they gold plated ?). Any ideas where I can look for "alternative" parts ? Can "non VW-standard" parts be fitted ? Is going for a "custom made" stainless a possibility ? Any recommendations or ideas gratefully received. Thx.