Interest in buying a V40

Hello, I once looked at the new V40 and also played something with the D4 on the configurator and would have a few questions since I have no idea of Volvo. 1. Is there a certain reason why Volvo has 5Cyl. with the 2l diesel? 2. Why there is no difference in consumption between the D3 and the D4? 3. What is the reliability Basically with the newer Volvo ́s (motor, transmission, electrics…) 4. The automatic transmission offered in the V40 is the more direction converter automatic or more direct transmission? 5. How is the processing generally, so when the car goes direction 4 or 5 years (folder noises..) 6. Is there a reason why there is no sunroof and only the panoramic roof? To the info I have until a short time allowed to call a Golf 6 GTD my own and am therefore looking for this again in this direction (optics, performance, processing…) Thank you already for your answers.