Mercedes Benz A Class A180 CDI Review

Had the car for 3 yrs, a CDI 180 Avantguard. Used mostly by my wife for work as a district nurse. The performance was way down on expected for a 2 litre diesel, don't believe its 80Kw, my 66Kw Focus feels much qicker. I fitted a Dragon performance chip which has made a big difference especially to the fuel economy, we can now get 60mpg plus with ease, why couldn' Mercedes make it like this? There have been reliability issues with the central locking, wipers & engine management, cost of spares is ridiculous £520 for 2 new rear door locks fitted @ the main dealers for example. On the plus side the comfort space & access is brilliant. A great car untill the warranty runs out.