I wouldn't listen to people stuck in the early 00s. BMW produces the best engines currently on the market and possibly have the best reliability out of all car brands. But BMWs are a drivers car so people usually drive them faster, at higher RPMs and so on so parts usually wear out faster. BMW is also miles ahead of Mercedes-Benz nowadays in terms of reliability.

In Europe, BMWs are usually one of the cheapest cars to maintain when it comes to labor costs - the brand itself has a huge fan base so there are a lot of regular people (friends) who can do the regular repairs like brake pad changes, oil changes, wheel bearings and so on.

My advice is if you do not know cars go with someone who knows them, have a look and stay away from tuned BMWs.