For this, we would suggest you walk into the nearest service centres as they will be better people to assist you. You can click on the following link to see the details of the nearest service centres and selecting your city accordingly - Service centre.
The difference between Mercedes Benz E-Class E200 and E220 is that E200 comes equipped with Rear Curtain, steering mounted touchpad to start things or off, etc. Moreover, you can click on the link to see the complete comparison details.
The Mercedes E 220d and E 350 d have a vast difference, both the cars get different engines. The Mercedes E 350d gets a V6 engine which churns 254.8bhp and produces amazing 620Nmn of torque. The E220d gets a 4 cylinder 1950cc engine which generates 191.7bhp of power and 400Nm of torque. Moreover, the E350d gets more features than the E 220d. Stay tuned.