Purchase advice Smart ForFour 1.3 95 HP

Hello dear Smart community, I am looking for a car (2nd car) for my wife. So we visited several car dealerships today to determine which vehicle my wife likes. We were not sure which manufacturer or which model fits my wife. At the end we ended up with a Mercedes dealer who also had some smart cars. Among other things, a ForFour. My wife was not enthusiastic about Smart at first. However, when we looked at the ForFour and sat down for the test (sampling didn’t go, was quite late) she was quite impressed by the car. Now my question(s): What do I have to pay attention to when buying such a car? And what about Alufelgen/winter tires? Is there only special or do I get something like that on the normal “tuning market”? I hope you can help a total smart layman a little bit further. Thank you already in advance!!!